Refrigeration oil composition

ABSTRACT

The refrigeration oil composition for HFC-based refrigerants or HC-based refrigerants of the invention includes a product of the esterification of an alcohol ingredient including pentaerythritol and dipentaerythritol and a fatty acid ingredient including at least one of a linear or branched fatty acid having 5 carbon atoms and a linear or branched fatty acid having 6 carbon atoms and at least one of a linear or branched fatty acid having 8 carbon atoms and a linear or branched fatty acid having 9 carbon atoms, wherein at least one of the fatty acid having 5 carbon atoms and the fatty acid having 6 carbon atoms in the fatty acid ingredient accounts for 20 to 100% by mol of the total amount of the fatty acid ingredient, and either the alcohol ingredient or the fatty acid ingredient is a mixture.

TECHNICAL FIELD

The present invention relates to a refrigeration oil compositionincluding a polyol ester oil which is soluble with eitherhydrofluorocarbon-based refrigerants or hydrocarbon-based refrigerants.

BACKGROUND ART

A refrigeration oil composition obtained by dissolving a refrigerant ina refrigeration oil is used as a working fluid in the refrigerationcycle in automotive air conditioners, domestic air conditioners, airconditioning within buildings, cold storehouses, refrigerators, and thelike, and hydrofluorocarbon-based refrigerants which contain no chlorineand are constituted of hydrogen, carbon, and fluorine are in use fromthe standpoint of environmental conservation. Polyol ester oils are usedaccordingly as refrigeration oils for dissolving thehydrofluorocarbon-based refrigerants therein (see, for example, patentdocument 1).

However, even refrigeration oil compositions containing the samehydrofluorocarbon-based refrigerant usually differ in requirementsconcerning the temperature at which the composition separates into therefrigeration oil and the refrigerant (two-layer separationtemperature), kinematic viscosity, etc. depending on applications orpurposes. Although it is generally necessary to lower the kinematicviscosity of a polyol ester oil for increasing the solubility of ahydrofluorocarbon-based refrigerant therein, the reduced kinematicviscosity results in a decrease in the lubricity of the refrigerationoil composition. Meanwhile, in cases when the lubricity is improved byheightening the kinematic viscosity of the polyol ester oil, thehydrofluorocarbon-based refrigerant comes to separate out.

There are hence cases where a polyol ester oil which is excellent interms of the solubility of hydrofluorocarbon-based refrigerants thereinand a polyol ester oil having excellent lubricity are mixed with eachother and used so as to result in solubility and kinematic viscositythat are suitable for the application or purpose (see, for example,patent documents 2 and 3). However, in case where the two polyol esteroils differ considerably in solubility with refrigerants, the polyolester oil which is less soluble in the refrigerant gradually separatesout, depending on the refrigerant used, during the period when therefrigeration oil composition circulates in the refrigeration cycle.

Meanwhile, since hydrofluorocarbon-based refrigerants have anexceedingly high global warming potential, hydrocarbon-basedrefrigerants, which are considerably low in global warming potentialalthough flammable, are employed in some applications. There is apossibility that such hydrocarbon-based refrigerants might beincreasingly used in various applications in future so long as apparatusmodification measures are taken to cope with the problem concerningflammability. As refrigeration oils for dissolving hydrocarbon-basedrefrigerants therein, use has been mainly made of naphthenic orparaffinic mineral oils, alkylbenzene oils, ether oils, fluorinatedoils, and the like. However, polyol ester-based lubricating oils havingcome to be used for the purpose of further improving lubricity. Forexample, an ester oil which is an ester of a neopentyl polyol includingneopentyl glycol or pentaerythritol with a branched monovalent fattyacid having 7 to 9 carbon atoms (see patent document 4) and a polyolester oil having an alkyl group having 11 to 19 carbon atoms (see patentdocument 5) are in use.

However, as in the case of hydrofluorocarbon-based refrigerants, suchrefrigeration oils usually differ in requirements concerning two-layerseparation temperature, kinematic viscosity, etc. depending on theapplications or purposes of the apparatus to be used. In addition, sincehydrocarbon-based refrigerants have an exceedingly low density which isabout one-half the density of hydrofluorocarbon-based refrigerants, thevolume concentration of a hydrocarbon-based refrigerant dissolved in arefrigeration oil even in the same weight concentration as before istwice and the viscosity, which is influenced by volume concentration, isconsiderably lower than the conventional refrigerant-solution viscosity.This decrease in refrigerant-solution viscosity is a factor which causesa decrease in lubricity. In the case of using a refrigerant and arefrigeration oil which have high solubility with each other, therefrigeration oil to be used is required to have high kinematicviscosity from the standpoint of heightening the refrigerant-solutionviscosity. However, since the refrigerant and the refrigeration oilconsiderably differ in density and because the refrigeration oil havingtoo high a viscosity has impaired flowability, the refrigerant and therefrigeration oil are less apt to mingle with each other in an actualmachine, resulting in a possibility that the refrigeration oil might besupplied in a reduced amount to the surfaces to be lubricated and thelubricity be impaired rather than improved.

However, the refrigeration oil described in patent document 4 has a lowviscosity (about 10 to 32 mm²/s at 40° C. according to Examples) and mayraise difficulties when used in large refrigerated facilities.Furthermore, the refrigeration oil described in patent document 5 isintended to be used with R290, and is usable only in limitedapplications.

Meanwhile, in production sites for producing refrigeration oils, it isnecessary that many kinds of polyol ester oils produced from a largenumber of raw materials are ready for use so as to be capable of copingwith differences in applications or purposes and in the kinds ofhydrofluorocarbon-based refrigerants, and this has resulted incomplexation of procurement of raw materials, production management, andproduct control. The polyol ester oils described in patent documents 2and 3 also are each intended to be suited for specific refrigerants andspecific apparatus, and when used in combination with other refrigerantsor in other apparatus, show too high or too low solubility with therefrigerants or have too high or too low viscosity. In particular, it isimpossible to obtain suitable solubility with less soluble refrigerants,such as difluoromethane (R-32) refrigerant, while ensuring necessaryviscosity.

The same applies to hydrocarbon-based refrigerants. Although it isnecessary that many kinds of refrigeration oils produced from a largenumber of raw materials are ready, the current prior-art techniquesincluding patent documents 4 and 5 are ineffective in overcoming suchproblems.

PRIOR-ART DOCUMENTS Patent Documents

Patent Document 1: Japanese Patent No. 2787083

Patent Document 2: Japanese Patent No. 3510888

Patent Document 3: JP-A-2010-235960

Patent Document 4: Japanese Patent No. 3909744

Patent Document 5: JP-A-2010-31134

SUMMARY OF THE INVENTION Problems that the Invention is to Solve

An object of the invention, which has been achieved in view of thecircumstances described above, is to provide a refrigeration oilcomposition which eliminates the necessity of making many kinds ofrefrigeration oils or raw materials therefor ready for coping withdifferences in applications or purposes and in the kinds of refrigerantsand which not only is free from separation between oils that have beenmixed together, but also is made to have solubility and viscosity thatare suitable for any of various hydrofluorocarbon-based refrigerants orhydrocarbon-based refrigerants and for any of various refrigeratedfacilities, by changing the ratio of specific raw materials.

Means for Solving the Problems

In order to accomplish the object, the present invention provides thefollowing refrigeration oil compositions.

(1) A refrigeration oil composition including a polyol ester oil whichis soluble with either a hydrofluorocarbon-based refrigerant or ahydrocarbon-based refrigerant,

wherein the polyol ester oil is a product of the esterification of analcohol ingredient including pentaerythritol and dipentaerythritol and afatty acid ingredient including at least one of a linear or branchedfatty acid having 5 carbon atoms and a linear or branched fatty acidhaving 6 carbon atoms and including at least one of a linear or branchedfatty acid having 8 carbon atoms and a linear or branched fatty acidhaving 9 carbon atoms,

at least one of the linear or branched fatty acid having 5 carbon atomsand linear or branched fatty acid having 6 carbon atoms in the fattyacid ingredient accounts for 20 to 100% by mol of the total amount ofthe fatty acid ingredient, and

either the alcohol ingredient or the fatty acid ingredient is a mixturecomposed of two components.

(2) The refrigeration oil composition according to (1) above,

wherein at least one of the fatty acids which constitute the fatty acidingredient is a branched fatty acid.

(3) The refrigeration oil composition according to (1) above,

wherein the fatty acid ingredient is a mixture of: at least one of2-methylbutanoic acid and 2-methylpentanoic acid; and at least one of2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid.

(4) The refrigeration oil composition according to (1) above,

wherein the fatty acid ingredient is a mixture of 2-methylbutanoic acidand 2-ethylhexanoic acid.

(5) The refrigeration oil composition according to any one of (1) to (4)above,

wherein the hydrofluorocarbon-based refrigerant includes at least onemember selected from R-32, R-410A, HFO-1234yf, and HFO-1234ze(E).

(6) The refrigeration oil composition according to any one of (1) to (4)above,

wherein the hydrocarbon-based refrigerant including at least one memberselected from R-290, R-600a, and R-1270.

(7) The refrigeration oil composition according to any one of (1) to (6)above, having a low-temperature-side two-layer separation temperatureand a high-temperature-side two-layer separation temperature, withrespect to separation from the hydrofluorocarbon-based refrigerant orhydrocarbon-based refrigerant as measured at an oil content of 20% byweight, of +20 degrees or lower and +35 degrees or higher, respectively.(8) The refrigeration oil composition according to any one of (1) to (7)above, containing at least one of an antioxidant, an epoxy-compound acidscavenger, and an extreme-pressure agent.

Advantage of the Invention

In the refrigeration oil composition of the invention, the polyol esteroil is a product of the esterification of a specific alcohol ingredientand a specific fatty acid ingredient, and has, in the molecule, both acomponent having excellent solubility with the hydrofluorocarbon-basedrefrigerant or hydrocarbon-based refrigerant and a component havingexcellent lubricity. Because of this, the refrigeration oil compositionis free from the separation between oils which occurs in the presence ofa refrigerant due to a difference therebetween in solubility with therefrigerant, as in the case where a plurality of polyol ester oils areused as a mixture thereof. In addition, the polyol ester oil does notseparate from the hydrofluorocarbon-based refrigerant orhydrocarbon-based refrigerant to stagnate in the refrigerating circuit.Since this refrigeration oil is made to have solubility and viscositythat are suitable for any of various hydrofluorocarbon-basedrefrigerants or hydrocarbon-based refrigerants and for any of variousrefrigerated facilities, by changing the ratio of specific rawmaterials, the refrigeration oil composition can satisfactorily andstably exhibit the lubricating performance and cooling performance inrefrigerated facilities.

Furthermore, the same alcohols and the same fatty acids can be used incommon for constituting the specific alcohol ingredient and the specificfatty acid ingredient, respectively, regardless of the kind of thehydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerant.Consequently, it is not necessary that raw materials for the polyolester oil are prepared for each refrigerant, as in conventionaltechniques, and the complexity of procurement of raw materials andproduction management can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is graphs which show the results of examinations for arelationship between open time and moisture content in oil, with respectto Example 2A and Comparative Example 1A.

FIG. 2 is graphs which show the results of examinations for arelationship between open time and moisture content in oil, with respectto Example 2B and Comparative Example 1B.

MODES FOR CARRYING OUT THE INVENTION

The refrigeration oil composition of the invention includes a polyolester oil. As the polyol ester oil, use is made of a product of theesterification of an alcohol ingredient including pentaerythritol anddipentaerythritol and a fatty acid ingredient including at least one ofa linear or branched fatty acid having 5 carbon atoms and a linear orbranched fatty acid having 6 carbon atoms and including at least one ofa linear or branched fatty acid having 8 carbon atoms and a linear orbranched fatty acid having 9 carbon atoms. It is, however, noted thateither the alcohol ingredient or the fatty acid ingredient is a mixturecomposed of two components. Meanwhile, since a fatty acid can be presentas a racemate, a substance which is one fatty acid but is a racemate isregarded as two kinds of fatty acids. This polyol ester oil can besynthesized so as to be applicable to any of various hydrofluorocarbonrefrigerants or hydrocarbon-based refrigerants which differ insolubility and to any of various refrigerated facilities which differ inrequired kinematic viscosity, by merely changing the ratio of componentswith respect to a specific combination of components of the alcoholingredient and fatty acid ingredient as raw materials.

Pentaerythritol and dipentaerythritol, which are used as the alcoholingredient, give an esterification product that not only has lubricitybut also is less apt to undergo influences of moisture, thesusceptibility to which is a drawback of ester compounds, and hasexceedingly high hydrolytic resistance. Furthermore, the solubility withthe hydrofluorocarbon-based refrigerant or hydrocarbon-based refrigerantand the affinity for metal surfaces can be regulated by selecting thekinds of the fatty acids to be used for the esterification. Sincedipentaerythritol is a dimer of pentaerythritol, a combination thereofwith pentaerythritol brings about excellent stability. By regulating theproportion of the pentaerythritol to the dipentaerythritol, theviscosity of the lubricating oil can be set to a value required by arefrigerated facility. Furthermore, by regulating thehigh-temperature-side two-layer separation temperature to a moresuitable value, lubricity within the compressor can be ensured.

The fatty acid ingredient is configured of at least one of a linear orbranched fatty acid having 5 carbon atoms (hereinafter inclusivelyreferred to as “pentanoic acid”) and a linear or branched fatty acidhaving 6 carbon atoms (hereinafter inclusively referred to as “hexanoicacid”) and containing a linear or branched fatty acid having 8 carbonatoms (hereinafter inclusively referred to as “octanoic acid”) and alinear or branched fatty acid having 9 carbon atoms (hereinafterinclusively referred to as “nonanoic acid”).

At least one of the pentanoic acid and hexanoic acid is a fatty acidingredient for improving solubility with the refrigerant. Although afatty acid ingredient having a smaller number of carbon atoms is moreeffective in improving solubility, use is made of the fatty acid(s)having 5 or 6 carbon atoms in order to ensure hydrolytic stability andviscosity to some degree. From the standpoint of ensuring the solubilityof the polyol ester oil with refrigerant R-32, which is especiallypoorly soluble, the upper limit of the length of the carbon chain inthis ingredient is 5 in terms of the number of carbon atoms; normalpentanoic acid is applicable but normal hexanoic acid is undesirable.This fatty acid serves also as an ingredient for regulating viscosityand ensuring lubricity, and heightens the polarity of the molecule tothereby reduce solubility and improve the affinity for metal surfaces.

At least one of the octanoic acid and nonanoic acid is a fatty acidingredient for ensuring viscosity and lubricity and for improvingsolubility with the refrigerant. A fatty acid ingredient having a largernumber of carbon atoms is more effective in improving viscosity and hasreduced polarity to improve solubility. However, in view of a decreasein solubility and from the standpoint of ensuring low-temperatureflowability and oxidative stability, use is made of the fatty acid(s)having 8 or 9 carbon atoms, which has been actually used forconventional refrigeration oils.

Especially from the standpoints of reducing adverse influences onsolubility and improving hydrolytic stability and viscosity, thebranched fatty acids are more preferred. Consequently, the branched formof each acid is more effective than the linear form thereof in enhancingthe solubility of the hydrofluorocarbon-based refrigerant orhydrocarbon-based refrigerant and is capable of further lowering thelow-temperature-side two-layer separation temperature. Furthermore,since the branched form is more effective in heightening viscosity thanthe linear form, use of the branched form facilitates the setting ofviscosity to that required by a refrigerated facility. In addition, thebranched form is capable of more improving hydrolytic stability than thelinear form. Consequently, a combination of fatty acid components whichconstitute the fatty acid ingredient and in which at least one is thebranched form is preferred to a combination in which all the fatty acidsare linear. Most preferred of such combinations is one in which all thefatty acids are branched.

The branched chains of the fatty acids preferably are methyl group orethyl group, and it is preferable that the number of branches in eachbranched fatty acid is 1 to 3. Furthermore, a preferred branchingposition is the 2-position, i.e., the position adjacent to the carboxylgroup. Preferred of such branched fatty acids are 2-methylbutanoic acidas a branched pentanoic acid, 2-methylpentanoic acid as a branchedhexanoic acid, 2-ethylhexanoic acid as a branched octanoic acid, and3,5,5-trimethylhexanoic acid as a branched nonanoic acid. Consequently,preferred as the fatty acid ingredient are mixtures of: at least one of2-methylbutanoic acid and 2-methylpentanoic acid; and at least one of2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid. Especiallypreferred is a mixture of 2-methylbutanoic acid and 2-ethylhexanoicacid.

In the invention, the kinematic viscosity of the polyol ester oil is 15to 350 mm²/s (40° C.), and is suitably selected in accordance with theapparatus in which the refrigeration oil composition is to be used andwith applications. Especially for air conditioners, it is preferablethat the kinematic viscosity of the polyol ester oil is 46 to 100 mm²/s(40° C.). Kinematic viscosities thereof less than 46 mm²/s (40° C.)result in poor lubricity, while kinematic viscosities thereof exceeding100 mm²/s (40° C.) result in too high viscosity resistance and aconsiderable decrease in performance. A more preferred range of thekinematic viscosity thereof is 50 to 80 mm²/s (40° C.). For smallrefrigerated facilities, it is preferable that the kinematic viscosityof the polyol ester oil is 22 to 68 mm²/s (40° C.). Kinematicviscosities thereof less than 22 mm²/s (40° C.) result in poorlubricity, while kinematic viscosities thereof exceeding 68 mm²/s (40°C.) result in too high viscosity resistance and a considerable decreasein performance. A more preferred range of the kinematic viscositythereof is 30 to 50 mm²/s (40° C.). For large refrigerated facilities,it is preferable that the kinematic viscosity of the polyol ester oil is68 to 320 mm²/s (40° C.). Kinematic viscosities thereof less than 68mm²/s (40° C.) result in poor lubricity or poor compressionchamber-sealing properties, while kinematic viscosities thereofexceeding 320 mm²/s (40° C.) result in too high viscosity resistance anda considerable decrease in performance. Since refrigerated facilitiesdiffer markedly in required kinematic viscosity depending on thecompressor and refrigeration system, it is necessary that the polyolester oil is regulated so as to have the kinematic viscosity required bya refrigerated facility. Such a kinematic viscosity may be attained byregulating the proportion in which pentaerythritol and dipentaerythritolare mixed together; pentaerythritol is used in an amount of 10 to 90% bymol based on the whole alcohol ingredient, with the remainder beingdipentaerythritol. In the case where it is necessary that a plurality ofpolyol ester oils which each are the polyol ester oil of the inventionand which differ in kinematic viscosity are mixed with each other, theresultant mixture can be used without suffering separation between theoils so long as the solubility of each polyol ester oil with therefrigerant to be used is appropriate. Especially for air conditioners,it is preferred to employ such a proportion that the amount ofpentaerythritol is 40 to 80% by mol based on the whole alcoholingredient, with the remainder being dipentaerythritol. For smallrefrigerated facilities, it is preferred to employ such a proportionthat the amount of pentaerythritol is 60 to 90% by mol based on thewhole alcohol ingredient, with the remainder being dipentaerythritol.For large refrigerated facilities, it is preferred to employ such aproportion that the amount of pentaerythritol is 10 to 40% by mol basedon the whole alcohol ingredient, with the remainder beingdipentaerythritol.

Meanwhile, the hydrofluorocarbon-based refrigerant to be dissolved inthe refrigeration oil composition is not particularly limited, and onewhich has conventionally been used as a refrigerant can be used, suchas, for example, R-134a (tetrafluoroethane) or R-410A (a mixture ofdifluoromethane and pentafluoroethane). It is, however, noted thatrequirements for environmental conservation are becoming severer and,especially in Europe, it was decided to use HFO-1234yf(2,3,3,3-tetrafluoro-1-propene) as a new refrigerant in the automotiveair conditioners of motor vehicles manufactured in and after the year2011 (2nd International Workshop on Mobile Air Conditioning andAuxiliary Systems-Trono, Italy Nov. 29, 2007 and European Automotive A/CConvention, Sep. 22-23, 2008). Besides that refrigerant, the followingare receiving attention as next-generation refrigerants: HFO-1234ze(E)(trans-1,3,3,3-tetrafluoro-1-propene), R-32 (difluoromethane), a mixtureof HFO-1234yf (2,3,3,3-tetrafluoro-1-propene) and R-32(difluoromethane), and a mixture of HFO-1234ze(E)(trans-1,3,3,3-tetrafluoro-1-propene) and R-32 (difluoromethane). In theinvention also, it is preferred to use HFO-1234yf, HFO-1234ze(E), orR-32 as the hydrofluorocarbon-based refrigerant. Any one of theserefrigerants and R-410A, which is a refrigerant used hitherto, may beused alone, or two or more thereof may be used as a mixture thereof. Inparticular, R-32 is receiving attention as a next-generation refrigerantsince R-32 has a low global warming potential (GWP), is not a mixedrefrigerant, and is relatively inexpensive. However, this refrigeranthas low solubility with conventional polyol ester oils and are prone tocause two-layer separation. According to the invention, however, byregulating the components of the alcohol ingredient and of the fattyacid ingredient and regulating the mixing proportions thereof, arefrigeration oil composition which is prevented from undergoingtwo-layer separation and has satisfactory lubricity is obtained evenwhen R-32 is used.

The hydrocarbon-based refrigerant also is not limited, and use can bemade of any one of hydrocarbon-based refrigerants which have hithertobeen used in some appliances, such as, for example, R-600a, R-290(propane), and R-1270 (propylene), or a mixture of two or more thereof.In particular, R-290 is receiving attention as a next-generationrefrigerant since R-290 has a low global warming potential (GWP), is nota mixed refrigerant, and is relatively inexpensive. However, thisrefrigerant has too high solubility with conventional naphthenic mineraloils to cause a decrease in viscosity due to the diluting effect of therefrigerant and is hence prone to cause a decrease in lubricity.According to the invention, however, by regulating the components of thealcohol ingredient and of the fatty acid ingredient and regulating themixing proportions thereof, a refrigeration oil composition havingsatisfactory lubricity is obtained using R-290.

In order to produce the refrigeration oil composition of the invention,a hydrofluorocarbon-based refrigerant or a hydrocarbon-based refrigerantis selected first. Thereafter, the mixing proportion of pentaerythritolto dipentaerythritol, the mixing proportion of at least one of pentanoicacid and hexanoic acid to at least one of octanoic acid and nonanoicacid, and the mixing proportion of the alcohol ingredient to the fattyacid ingredient are set while taking account of solubility with theselected refrigerant and lubricity, and the alcohol ingredient issubjected to esterification reaction with the fatty acid ingredient toproduce a polyol ester oil.

In the refrigeration oil composition, it is preferable that with respectto separation from the hydrofluorocarbon-based refrigerant orhydrocarbon-based refrigerant, the high-temperature-side two-layerseparation temperature is +35° C. or higher, in particular, in the rangeof +40 to +65° C., and the low-temperature-side two-layer separationtemperature is +20° C. or lower, in particular, 0° C. or lower. For usein refrigerated facilities or large air conditioners, there is a requestfor −30° C. or lower, or for −50° C. or lower. Such solubility can beobtained by regulating the mixing proportion of at least one of thepentanoic acid and hexanoic acid to at least one of the octanoic acidand nonanoic acid in the fatty acid ingredient. Specifically, the amountof at least one of pentanoic acid and hexanoic acid is regulated to 20to 100% by mol based on the whole fatty acid ingredient, with theremainder being at least one of octanoic acid and nonanoic acid.Especially for domestic air conditioners in which R-32 is used, apreferred proportion is one in which 2-methylbutanoic acid is used in anamount of 40 to 60% by mol, with the remainder being 2-ethylhexanoicacid.

In case where the high-temperature-side two-layer separation temperatureis not +35° C. or higher and the low-temperature-side two-layerseparation temperature is not +20° C. or lower, the solubility betweenthe polyol ester oil and the hydrofluorocarbon-based refrigerant orhydrocarbon-based refrigerant is insufficient and separation between thetwo occurs in high-temperature parts of the refrigeration cycle, e.g.,the condenser, and in low-temperature parts thereof, e.g., theevaporator. Once the separation occurs, the following adverse influencesare exerted thereby: the polyol ester oil stagnates in heat exchangers,such as the condenser and the evaporator, to inhibit heat exchange; theamount of the polyol ester oil which returns to the compressor decreasesto cause compressor troubles due to insufficient lubrication; and theseparation inhibits refrigerant circulation to thereby considerablylower the cooling performance. Incidentally, any polyol ester oilproduced from one alcohol and one fatty acid is prone to crystallize orsolidify at room temperature to low temperatures and hence cannot beadopted. In addition, it is noted that in cases when a fatty acid whichis apparently constituted of one component but is a racemate isemployed, this fatty acid is regarded as being constituted of twocomponents. Consequently, 2-methylbutanoic acid, which is a pentanoicacid, is more effective in preventing crystallization than3-methylbutanoic acid, which also is a pentanoic acid, and2-methylpentanoic acid, which is a hexanoic acid, is more effective inpreventing crystallization, than 2-ethylbutanoic acid, which also is ahexanoic acid.

In particular, for refrigerated facilities or large air conditioners inwhich R-32 is used, a preferred proportion is one in which2-methylbutanoic acid is used in an amount of 60 to 90% by mol, with theremainder being 2-ethylhxanoic acid. For refrigerated facilities inwhich HFO-1234ze(E) is used, preferred are a proportion in which2-methylbutanoic acid is used in an amount of 20 to 60% by mol, with theremainder being 2-ethylhexanoic acid, and a proportion in which2-methylpentanoic acid is used in an amount of 20 to 60% by mol, withthe remainder being 3,5,5-trimethylhexanoic acid.

There are no limitations on the esterification reaction, and thereaction can be conducted in accordance with methods in practical use.In the esterification reaction, the carboxyl groups of the fatty acidsreact with all the hydroxyl groups of the alcohols. Consequently, oncethe mixing proportion of pentaerythritol to dipentaerythritol in thealcohol ingredient is decided, the total amount of hydroxyl groups inthe mixture is also determined and, hence, the amount of the fatty acidingredient to be used may be set in accordance with the total amount ofhydroxyl groups.

Processes for producing the refrigeration oil composition arespecifically shown below. For example, in the case where HFO-1234ze(E)has been selected as a hydrofluorocarbon-based refrigerant for smallrefrigerated facilities and where the required kinematic viscosity at40° C. is 15 to 60 mm²/s, then an alcohol ingredient in whichpentaerythritol accounts for 60 to 100% by mol thereof, with theremainder being dipentaerythritol, and a fatty acid ingredient in which2-methylbutanoic acid accounts for 20 to 90% by mol thereof, with theremainder being at least one of 2-ethylhexanoic acid and3,5,5-trimethylhexanoic acid, are used and esterified to produce apolyol ester oil. Thereafter, HFO-1234ze(E) is dissolved in this polyolester oil to obtain a refrigeration oil composition. The refrigerationoil composition thus obtained satisfies the high-temperature-sidetwo-layer separation temperature, low-temperature-side two-layerseparation temperature, and kinematic viscosity described above and isexcellent in terms of refrigerating performance and lubricatingperformance.

Meanwhile, in the case where, for example, HFO-1234ze(E) has beenselected for large refrigerated facilities and where the requiredkinematic viscosity at 40° C. is 90 to 240 mm²/s, then use is made ofeither a polyol ester oil obtained by esterifying an alcohol ingredientin which pentaerythritol accounts for 0 to 70% by mol thereof, with theremainder being dipentaerythritol, and a fatty acid ingredient in whichat least one of 2-methylbutanoic acid and 2-methylpentanoic acidaccounts for 20 to 60% by mol thereof, with the remainder being2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying analcohol ingredient in which pentaerythritol accounts for 40 to 100% bymol thereof, with the remainder being dipentaerythritol, and a fattyacid ingredient in which at least one of 2-methylbutanoic acid and2-methylpentanoic acid accounts for 20 to 60% by mol thereof, with theremainder being 3,5,5-trimethylhexanoic acid. HFO-1234ze(E) is dissolvedin this polyol ester oil to obtain a refrigeration oil composition.

Furthermore, in the case where, for example, R-32 has been selected fordomestic air conditioners and where the required kinematic viscosity at40° C. is 40 to 80 mm²/s, then use is made of either a polyol ester oilobtained by esterifying an alcohol ingredient in which pentaerythritolaccounts for 40 to 80% by mol thereof, with the remainder beingdipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoicacid accounts for 40 to 70% by mol thereof, with the remainder being2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying analcohol ingredient in which pentaerythritol accounts for 50 to 100% bymol thereof, with the remainder being dipentaerythritol, and a fattyacid ingredient in which 2-methylbutanoic acid accounts for 30 to 70% bymol thereof, with the remainder being 3,5,5-trimethylhexanoic acid. R-32is dissolved in this polyol ester oil to obtain a refrigeration oilcomposition.

Moreover, also in the case of a conventional mode in which R-410A isselected for domestic air conditioners, use can be made of a polyolester oil obtained by esterifying an alcohol ingredient in whichpentaerythritol accounts for 40 to 80% by mol thereof, with theremainder being dipentaerythritol, and a fatty acid ingredient in which2-methylbutanoic acid accounts for 40 to 70% by mol thereof, with theremainder being 2-ethylhexanoic acid. R-410A is dissolved in this polyolester oil to obtain a refrigeration oil composition.

Furthermore, also in the case of a conventional mode in which R-410A isselected for large air conditioners, use can be made of a polyol esteroil obtained by esterifying an alcohol ingredient in whichpentaerythritol accounts for 40 to 80% by mol thereof, with theremainder being dipentaerythritol, and a fatty acid ingredient in which2-methylbutanoic acid accounts for 40 to 60% by mol thereof, with theremainder being 2-ethylhexanoic acid. R-410A is dissolved in this polyolester oil to obtain a refrigeration oil composition.

Moreover, also in the case where R-32, which is a next-generationrefrigerant, and R-410A, which is a conventional refrigerant, minglewith each other in a large air conditioner because of, for example, theconfiguration of the facilities, use can be made of a polyol ester oilobtained by esterifying an alcohol ingredient in which pentaerythritolaccounts for 40 to 80% by mol thereof, with the remainder beingdipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoicacid accounts for 40 to 60% by mol thereof, with the remainder being2-ethylhexanoic acid. A mixed refrigerant composed of R-32 and R-410A isdissolved in this polyol ester oil to obtain a refrigeration oilcomposition.

Furthermore, in the case where a mixed refrigerant composed of R-32 andeither HFO-1234yf or HFO-1234ze(E) has been selected for domestic airconditioners and where the required kinematic viscosity at 40° C. is 40to 80 mm²/s, then use is made of either a polyol ester oil obtained byesterifying an alcohol ingredient in which pentaerythritol accounts for40 to 80% by mol thereof, with the remainder being dipentaerythritol,and a fatty acid ingredient in which 2-methylbutanoic acid accounts for20 to 50% by mol thereof, with the remainder being 2-ethylhexanoic acid,or a polyol ester oil obtained by esterifying an alcohol ingredient inwhich pentaerythritol accounts for 50 to 100% by mole thereof, with theremainder being dipentaerythritol, and a fatty acid ingredient in which2-methylbutanoic acid accounts for 30 to 70% by mol thereof, with theremainder being 3,5,5-trimethylhexanoic acid. A mixed refrigerantcomposed of R-32 and either HFO-1234yf or HFO-1234ze(E) is dissolved inthe polyol ester oil to obtain a refrigeration oil composition.

Furthermore, in the case where R-290 has been selected as ahydrocarbon-based refrigerant for small refrigerated facilities andwhere the required kinematic viscosity at 40° C. is 15 to 60 mm²/s, thenan alcohol ingredient in which pentaerythritol accounts for 60 to 100%by mol thereof, with the remainder being dipentaerythritol, and a fattyacid ingredient in which 2-methylbutanoic acid accounts for 20 to 90% bymol thereof, with the remainder being at least one of 2-ethylhexanoicacid and 3,5,5-trimethylhexanoic acid, are used and esterified toproduce a polyol ester oil. Such a refrigeration oil compositionsatisfies the high-temperature-side two-layer separation temperature,low-temperature-side two-layer separation temperature, and kinematicviscosity described above and is excellent in terms of refrigeratingperformance and lubricating performance.

Furthermore, in the case where, for example, R-1270 has been selectedfor large refrigerated facilities and where the required kinematicviscosity at 40° C. is 90 to 240 mm²/s, then use is made of either apolyol ester oil obtained by esterifying an alcohol ingredient in whichpentaerythritol accounts for 0 to 70% by mole thereof, with theremainder being dipentaerythritol, and a fatty acid ingredient in whichat least one of 2-methylbutanoic acid and 2-methylpentanoic acidaccounts for 20 to 60% by mol thereof, with the remainder being2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying analcohol ingredient in which pentaerythritol accounts for 40 to 100% bymol thereof, with the remainder being dipentaerythritol, and a fattyacid ingredient in which at least one of 2-methylbutanoic acid and2-methylpentanoic acid accounts for 20 to 60% by mol thereof, with theremainder being 3,5,5-trimethylhexanoic acid.

Furthermore, in the case where, for example, R-290 has been selected fordomestic air conditioners and where the required kinematic viscosity at40° C. is 40 to 80 mm²/s, then use is made of either a polyol ester oilobtained by esterifying an alcohol ingredient in which pentaerythritolaccounts for 40 to 80% by mol thereof, with the remainder beingdipentaerythritol, and a fatty acid ingredient in which 2-methylbutanoicacid accounts for 40 to 70% by mol thereof, with the remainder being2-ethylhexanoic acid, or a polyol ester oil obtained by esterifying analcohol ingredient in which pentaerythritol accounts for 50 to 100% bymol thereof, with the remainder being dipentaerythritol, and a fattyacid ingredient in which 2-methylbutanoic acid accounts for 30 to 70% bymol thereof, with the remainder being 3,5,5-trimethylhexanoic acid.

Furthermore, in the case where, for example, a mixed refrigerantcomposed of R-290 and R-1270 has been selected for domestic airconditioners and where the required kinematic viscosity at 40° C. is 40to 80 mm²/s, then use is made of either a polyol ester oil obtained byesterifying an alcohol ingredient in which pentaerythritol accounts for40 to 80% by mol thereof, with the remainder being dipentaerythritol,and a fatty acid ingredient in which 2-methylbutanoic acid accounts for20 to 50% by mol thereof, with the remainder being 2-ethylhexanoic acid,or a polyol ester oil obtained by esterifying an alcohol ingredient inwhich pentaerythritol accounts for 50 to 100% by mol thereof, with theremainder being dipentaerythritol, and a fatty acid ingredient in which2-methylbutanoic acid accounts for 30-70% by mol thereof, with theremainder being 3,5,5-trimethylhexanoic acid.

As described above, by using pentaerythritol, dipentaerythritol, atleast one of pentanoic acid and hexanoic acid, and at least one ofoctanoic acid and nonanoic acid in common and by merely changing themixing proportions thereof, polyol ester oils which are usable withvarious hydrofluorocarbon-based refrigerants or hydrocarbon-basedrefrigerants are obtained. Consequently, to prepare pentaerythritol,dipentaerythritol, at least one of pentanoic acid and hexanoic acid, andat least one of octanoic acid and nonanoic acid beforehand suffices forthe production site, and the complexation of raw material procurementand of production management can be significantly reduced as comparedwith the case where many kinds of polyol ester oils are prepared.

Various additives can be added to the refrigeration oil composition ofthe invention. The polyol ester oil has the possibility of undergoingoxidative deterioration or hydrolysis due to the outside air or moisturewhich has infiltrated into the refrigeration cycle or due to theinfluence of residues, e.g., a rust preventive, which remain in therefrigeration cycle, resulting in a possibility that an acidic componentmight be produced by the deterioration or hydrolysis to corrode theinside of the system. Furthermore, refrigerants having a double bond inthe molecule, such as HFO-1234yf, HFO-1234ze(E), and R-1270, are moreprone, than other hydrofluorocarbon-based refrigerants, to undergooxidative deterioration or hydrolysis due to heat or the outside air ormoisture which has infiltrated into the refrigeration cycle or due tothe influence of residues, e.g., a rust preventive, which remain in therefrigeration cycle, resulting in a possibility that an acidic componentmight be produced by the deterioration or hydrolysis to corrode theinside of the system. It is therefore preferred to add an epoxy-compoundacid scavenger. In particular, epoxy-compound acid scavengers such asglycidyl ethers and glycidyl esters are preferred since such compoundshave a high acid-scavenging effect. Furthermore, it is preferred to usean epoxy-compound acid scavenger having an epoxycycloalkyl group or anepoxy-compound acid scavenger obtained by introducing a glycidyl groupinto an end of polypropylene glycol, from the standpoint of affinity forthe polyol ester oil and hydrofluorocarbon-based refrigerant. Moreover,an epoxy-compound acid scavenger obtained by introducing a glycidylgroup into an alcohol or fatty acid having 10 or less carbon atoms ispreferred since this compound shows improved acid-scavenging ability dueto the high dispersibility thereof in the hydrofluorocarbon-basedrefrigerant or hydrocarbon-based refrigerant.

By adding a lubricity improver, such as an extreme-pressure agent or anoiliness agent, not only the metallic surfaces of sliding portions canbe prevented from wearing or seizing but also the lubricity is enhancedto reduce frictional heating, making it possible to inhibit thedecomposition of refrigerants having a double bond in the molecule, suchas HFO-1234yf, HFO-1234ze(E), and R-1270. As the extreme-pressure agent,use may be made of a phosphoric acid type extreme-pressure agent or athiophosphoric acid type extreme-pressure agent in accordance withrequirements of the refrigerated facility or air conditioner. Sincethiophosphoric acid type extreme-pressure agents cause precipitation ofa sulfur compound depending on the conditions and it is hence necessaryto minimize the amount thereof if these agents are added, phosphoricacid type extreme-pressure agents are preferred. Examples of thephosphoric acid type extreme-pressure agents include tricresylphosphate, triphenyl phosphate, tris(tert-butylphenyl)phosphate,monophenyl bis(tert-butylphenyl)phosphate, and diphenyl tert-butylphenylphosphate. As the oiliness agent, use may be made of one which has noactive element, e.g., phosphorus or sulfur, and which utilizes theaffinity of oxygen for metals, such as a long-chain-alkyl alcohol, alkylmonoglyceride, or fatty acid methyl ester. Examples thereof includeoleyl alcohol, isostearyl alcohol, oleyl monoglyceride, linolenylmonoglyceride, and methyl oleate.

It is also preferred to add an antioxidant in order to inhibitrefrigerants having a double bond in the molecule, such as HFO-1234yf,HFO-1234ze(E), and R-1270, from decomposing or from undergoing oxidativedeterioration due to the infiltration of outside air into therefrigeration cycle. Examples of the antioxidant include phenolicantioxidants such as 2,6-di-tert-butyl-4-methylphenol,2,6-di-tert-butyl-4-ethylphenol, and2,2′-methylenebis(4-methyl-6-tert-butylphenol) and amine-compoundantioxidants such as phenyl-α-naphthylamine andN,N′-diphenyl-p-phenylenediamine. However, since the amine-compoundantioxidants have reactivity with refrigerants having a double bond inthe molecule, such as HFO-1234yf, HFO-1234ze(E), and R-1270, it ispreferred to use these antioxidants in the refrigeration oil to beapplied to other hydrofluorocarbon-based refrigerants or tohydrocarbon-based refrigerants.

Any one of the epoxy-compound acid scavenger, lubricity improver, andantioxidant may be used alone, or the three agents can be used incombination. There are no limitations on the amount of each agent to beadded, so long as the effect thereof is produced. It is, however,preferable that the amounts of the epoxy-compound acid scavenger,lubricity improver, and antioxidant are 0.25 to 2% by mass, 0.5 to 4% bymass, and 0.1 to 1% by mass, respectively, based on the wholerefrigeration oil composition. In case where the addition amount of eachagent is less than the lower limit, the effect thereof cannot besufficiently produced. Even when the amount of each agent is larger thanthe upper limit, not only the effect is not enhanced any more, but alsothe relative content of the polyol ester oil is low, resulting in poorlubricity.

In addition to those additives, additives in general use may be addedfor the purpose of improving performances other than those mentionedabove.

EXAMPLES

Test Examples are shown below to further explain the invention, but theinvention should not be construed as being limited by the followingExamples in any way. Incidentally, Test A relates to refrigeration oilcompositions for hydrofluorocarbon-based refrigerants, while Test Brelates to refrigeration oil compositions for hydrocarbon-basedrefrigerants.

<Test A: Refrigeration Oil Compositions for Hydrofluorocarbon-BasedRefrigerants>

The alcohol ingredients and fatty acid ingredients shown in Table A wereesterified to produce polyol ester oils. In the table, PE representspentaerythritol, DiPE represents dipentaerythritol, LPt representsnormal pentanoic acid (a pentanoic acid), 2 MBu representsDL-2-methylbutanoic acid (a pentanoic acid), LHx represents normalhexanoic acid (a hexanoic acid), 2 MPt represents DL-2-methylpentanoicacid (a hexanoic acid), 2EBu represents 2-ethylbutanoic acid (a hexanoicacid), 2EHx represents a 2-ethylhexanoic acid (an octanoic acid), andTMHx represents 3,5,5-trimethylhexanoic acid (a nonanoic acid), and themixing proportion of each alcohol ingredient to the fatty acidingredient is in molar ratio. A poly(vinyl ether) oil (comparative oil15A) which is currently in use as a refrigeration oil was added as acomparative oil besides ester oils produced from the alcohol ingredientand fatty acid ingredient. Furthermore, comparative oils 18A, 19A, and20A were added as mixed oils. The refrigeration oil A used in the mixedoils is in use as a refrigeration oil for HFC refrigerators; thisrefrigeration oil is highly soluble with refrigerant R-32 but has toolow viscosity to be used as such in the refrigerated facilities or airconditioners to which the invention is intended to be applied.

TABLE A (Polyol ester oils used in Examples and Comparative Examples)Alcohol ingredient Fatty acid ingredient Oil No. PE DiPE Acid 1 Acid 2Synthetic oil 1A 0.60 0.40 2MBu: 0.4 2EHx: 0.6 Synthetic oil 2A 0.550.45 2MBu: 0.5 2EHx: 0.5 Synthetic oil 3A 0.55 0.45 2MBu: 0.7 2EHx: 0.3Synthetic oil 4A 0.55 0.45 2MBu: 0.85 2EHx: 0.15 Synthetic oil 5A 0.300.70 2MBu: 0.5 2EHx: 0.5 Synthetic oil 6A 0.55 0.45 2MBu: 0.45 2EHx:0.55 Synthetic oil 7A 1.0 0.0 2MBu: 0.5 TMHx: 0.5 Synthetic oil 8A 0.500.50 2MBu: 1.0 TMHx: 0.0 Synthetic oil 9A 1.0 0.0 2MBu: 0.4 TMHx: 0.6Synthetic oil 10A 0.85 0.15 2MBu: 0.6 TMHx: 0.4 Synthetic oil 11A 0.01.0 LPt: 0.8 TMHx: 0.2 Synthetic oil 12A 0.25 0.75 2MPt: 0.8 2EHx: 0.2Synthetic oil 13A 0.25 0.75 2MPt: 1.0 — Synthetic oil 14A 1.0 0.0 2MPt:0.5 TMHx: 0.5 Synthetic oil 15A 1.0 0.0 2EBu: 0.75 TMHx: 0.25 Syntheticoil 16A 0.0 1.0 2MBu: 0.5 2EHx: 0.5 Synthetic oil 17A 0.0 1.0 2MBu: 0.652EHx: 0.35 Synthetic oil 18A 0.0 1.0 2MBu: 1.0 — Synthetic oil 19A 0.100.90 2MBu: 1.0 — Synthetic oil 20A 0.70 0.30 2MBu: 0.5 TMHx: 0.5Synthetic oil 21A 0.50 0.50 2MBu: 0.5 TMHx: 0.5 Synthetic oil 22A 0.300.70 2MBu: 0.5 TMHx: 0.5 Synthetic oil 23A 0.0 1.0 2MBu: 0.9 TMHx: 0.1Synthetic oil 24A 0.0 1.0 2MBu: 0.65 TMHx: 0.35 Synthetic oil 25A 0.01.0 2MBu: 0.5 TMHx: 0.5 Synthetic oil 26A 1.0 0.0 LPt: 0.5 2EHx: 0.5Synthetic oil 27A 1.0 0.0 LPt: 0.75 TMHx: 0.25 Synthetic oil 28A 1.0 0.0LPt: 0.5 TMHx: 0.5 Synthetic oil 29A 1.0 0.0 2MBu: 1.0 — Synthetic oil30A 1.0 0.0 2MBu: 0.75 2EHx: 0.25 Synthetic oil 31A 1.0 0.0 2MBu: 0.52EHx: 0.5 Synthetic oil 32A 0.70 0.30 2MBu: 0.85 2EHx: 0.15 Syntheticoil 33A 1.0 0.0 2MBu: 0.75 TMHx: 0.25 Synthetic oil 34A 1.0 0.0 2MPt:1.0 — Synthetic oil 35A 1.0 0.0 2MPt: 0.75 2EHx: 0.25 Comparative oil 1A1.0 0.0 2EHx: 0.5 TMHx: 0.5 Comparative oil 2A 1.0 0.0 LHx: 0.25 TMHx:0.75 Comparative oil 3A 0.0 1.0 LHx: 0.65 TMHx: 0.35 Comparative oil 4A0.0 1.0 LHx: 1.0 — Comparative oil 5A 1.0 0.0 2EBu: 1.0 — Comparativeoil 6A 0.65 0.35 2EHx: 1.0 — Comparative oil 7A 0.0 1.0 LHx: 0.35 TMHx:0.65 Comparative oil 8A 1.0 0.0 TMHx: 1.0 — Comparative oil 9A 0.0 1.02EHx: 0.5 TMHx: 0.5 Comparative oil 10A 0.0 1.0 2MPt: 0.35 2EHx: 0.65Comparative oil 11A 1.0 0.0 2EHx: 1.0 — Comparative oil 12A 1.0 0.0 LPt:0.25 2EHx: 0.75 Comparative oil 13A 1.0 0.0 LHx: 0.5 TMHx: 0.5Comparative oil 14A 1.0 0.0 2MPt: 0.25 2EHx: 0.75 Comparative oil 15Arefrigerant R-410A/ether oil for air conditioner Comparative oil 16Acomplex ester obtained from PE, 2EHx, adipic acid, etc. Comparative oil17A 0.8 0.2 LPt: 0.4 n-heptanoic acid: 0.4 TMHx: 0.2 Comparative oil 18Amixed oil (refrigeration oil A, 25 wt % + comparative oil 1, 75 wt %)Makeup of refrigeration oil A Alcohol: neopentyl glycol Fatty acid: 2EHxComparative oil 19A mixed oil (refrigeration oil A, 50 wt % +comparative oil 9, 50 wt %) Makeup of refrigeration oil A Alcohol:neopentyl glycol Fatty acid: 2EHx Comparative oil 20A mixed oil(refrigeration oil A, 30 wt % + comparative oil 16, 70 wt %) Makeup ofrefrigeration oil A Alcohol: neopentyl glycol Fatty acid: 2EHx Note 1)Comparative oil 1A and comparative oil 15A are in use in airconditioners where R-410A, which is a current refrigerant, is used. Note2) Although synthetic oil 18A appears to be produced from one alcoholand one fatty acid, it has been ascertained that the fatty acid was aracemate and composed of two components and, hence, the oil does notsolidify. Note 3) Comparative oil 16A is in use in large refrigeratedfacilities or air conditioners where R-410A, 407C, 134a, and 404A, whichare current refrigerants, are used. Note 4) Although synthetic oils 29Aand 34A each appear to be produced from one alcohol and one fatty acid,it has been ascertained that the fatty acid was a racemate and composedof two components and, hence, the oil does not solidify. Note 5)Synthetic oil 17A is in use in refrigerated facilities or airconditioners where R-134a and 404A, which are current refrigerants, areused. Note 6) Refrigeration oil A used in comparative oils 18A to 20A isin use in refrigeration oils for HFC-refrigerant refrigerators.Two-layer separation temperatures for refrigeration oil A andrefrigerant R-32 (oil content, 20 wt %): high temperature, +70° C. orhigher; low temperature, −20° C. Kinematic viscosity of refrigerationoil A: 7.56 (40° C.), 2.07 (100° C.)

Test Example 1A: With Respect to Kinematic Viscosities of Each PolyolEster Oil Synthesized

Each of the polyol ester oils and comparative oils was examined forkinematic viscosity at 40° C. and 100° C. The results of the measurementare shown in Tables 3 and 4.

TABLE 3 Kinematic viscosity mm²/s mm²/s Example No. Oil No. (40° C.)(100° C.) Remarks Example 1A synthetic oil 1A 69.7 8.67 — Example 2Asynthetic oil 2A 66.9 8.42 — Example 3A synthetic oil 3A 66.0 8.39 —Example 4A synthetic oil 4A 64.5 8.20 — Example 5A synthetic oil 5A 97.810.9 — Example 6A synthetic oil 6A 75.1 9.10 — Example 7A synthetic oil7A 60.0 7.76 — Example 8A synthetic oil 8A 66.1 8.23 — Example 9Asynthetic oil 9A 64.4 8.20 — Example 10A synthetic oil 10A 62.5 7.98 —Example 11A synthetic oil 11A 67.1 9.88 — Example 12A synthetic oil 12A69.0 9.26 — Example 13A synthetic oil 13A 61.8 8.71 — Example 14Asynthetic oil 14A 53.9 7.39 — Example 15A synthetic oil 15A 70.0 6.99 —Example 16A synthetic oil 16A 140 13.8 — Example 17A synthetic oil 17A139 13.6 — Example 18A synthetic oil 18A 141 13.6 — Example 19Asynthetic oil 19A 124 12.4 — Example 20A synthetic oil 20A 108 11.4 —Example 21A synthetic oil 21A 149 14.0 — Example 22A synthetic oil 22A196 16.7 — Example 23A synthetic oil 23A 164 15.0 — Example 24Asynthetic oil 24A 225 18.3 — Example 25A synthetic oil 25A 276 20.9 —Example 26A synthetic oil 26A 27.8 4.99 — Example 27A synthetic oil 27A24.8 4.88 — Example 28A synthetic oil 28A 42.7 6.69 — Example 29Asynthetic oil 29A 25.7 4.39 — Example 30A synthetic oil 30A 29.4 4.83 —Example 31A synthetic oil 31A 36.8 5.47 — Example 32A synthetic oil 32A47.3 6.48 — Example 33A synthetic oil 33A 37.3 5.66 — Example 34Asynthetic oil 34A 22.4 4.31 — Example 35A synthetic oil 35A 26.0 4.67 —

TABLE 4 Kinematic viscosity Comparative mm²/s mm²/s Example No. Oil No.(40° C.) (100° C.) Remarks Comparative comparative 67.8 8.34 — Example1A oil 1A Comparative comparative 64.6 8.50 — Example 2A oil 2AComparative comparative 88.0 11.9 — Example 3A oil 3A Comparativecomparative 53.0 8.72 solidified at Example 4A oil 4A room temperatureComparative comparative 54.0 6.36 solidified at Example 5A oil 5A roomtemperature Comparative comparative 70.4 8.74 — Example 6A oil 6AComparative comparative 181 17.6 — Example 7A oil 7A Comparativecomparative 114 11.5 solidified at Example 8A oil 8A room temperatureComparative comparative 228 19.2 — Example 9A oil 9A Comparativecomparative 116 12.9 — Example 10A oil 10A Comparative comparative 44.36.26 — Example 11A oil 11A Comparative comparative 34.1 5.44 — Example12A oil 12A Comparative comparative 40.5 6.58 — Example 13A oil 13AComparative comparative 36.4 5.60 — Example 14A oil 14A Comparativecomparative 64.7 7.95 — Example 15A oil 15A Comparative comparative 22621.8 — Example 16A oil 16A Comparative comparative 30.3 5.73 — Example17A oil 17A Comparative comparative 33.8 5.44 — Example 18A oil 18AComparative comparative 32.4 5.42 — Example 19A oil 19A Comparativecomparative 67.4 9.42 — Example 20A oil 20A

Test 2A: With Respect to Solubility with R-32

Each polyol ester oil and R-32 were enclosed in a glass tube so as toresult in an oil content of 20% by weight, and the glass tube was shakento dissolve the R-32 in the polyol ester oil. After the dissolution, theglass tube was placed in a water bath and gradually heated to measurethe temperature at which the even layer separated into an oil layer anda refrigerant layer (high-temperature-side two-layer separationtemperature). Meanwhile, the glass tube was placed in a cooling chamberand gradually cooled to measure the temperature at which the even layerseparated into an oil layer and a refrigerant layer(low-temperature-side two-layer separation temperature).

The results of the measurements and the kinematic viscosities are bothshown in Table 5 to Table 7.

TABLE 5 Refrigerant R-32/air conditioner (as refrigeration oil havingkinematic viscosity at 40° C. of 50-100 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 36Asynthetic oil 1A +48 +16 69.7 Example 37A synthetic oil 2A +58 −6 66.9Example 38A synthetic oil 3A +68 −30 66.0 Example 39A synthetic oil 4A+70 or higher −50 64.5 Example 40A synthetic oil 5A +52 +4 97.8 Example41A synthetic oil 6A +51 +9 75.1 Example 42A synthetic oil 7A +67 −1360.0 Example 43A synthetic oil 8A +70 or higher −50 or lower 66.1Example 44A synthetic oil 9A +62 −2 64.4 Example 45A synthetic oil 10A+68 −24 62.5 Example 46A synthetic oil 11A +54 −12 67.1 Example 47Asynthetic oil 12A +46 −1 69.0 Example 48A synthetic oil 13A +61 −18 61.8Example 49A synthetic oil 14A +57 +7 53.9 Example 50A synthetic oil 15A+56 +10 70.0 Comparative comparative oil 1A separated separated 67.8Example 18A throughout throughout the whole range the whole rangeComparative comparative oil 2A separated separated 64.6 Example 19Athroughout throughout the whole range the whole range Comparativecomparative oil 3A Separated separated 88.0 Example 20A throughoutthroughout the whole range the whole range Comparative comparative oil4A Separated separated 53.0 Example 21A throughout throughout the wholerange the whole range Comparative comparative oil 5A +70 or higher −1454.0 Example 22A solidified at room temperature Comparative comparativeoil 6A Separated separated 70.4 Example 23A throughout throughout thewhole range the whole range Comparative comparative oil separatedseparated 64.7 Example 24A 15A throughout throughout the whole range thewhole range Comparative comparative oil separated separated 67.4 Example25A 20A throughout throughout the whole range the whole range

TABLE 6 Refrigerant R-32/large refrigerated facility or air conditioner(as refrigeration oil having kinematic viscosity at 40° C. of 100-320mm²/s) Properties High-temperature- Low-temperature- Example sidetwo-layer side two-layer Kinematic Comparative separation separationviscosity Example temperature temperature (40° C.) No. Oil No. ° C. ° C.mm²/s Example 51A synthetic oil 16A +45 +10 140 Example 52A syntheticoil 17A +57 −14 139 Example 53A synthetic oil 18A +70 or higher −50 orlower 141 Example 54A synthetic oil 19A +70 or higher −50 or lower 124Example 55A synthetic oil 20A +61 −3 108 Example 56A synthetic oil 21A+56 −1 149 Example 57A synthetic oil 22A +52 +8 196 Example 58Asynthetic oil 23A +70 or higher −50 or lower 164 Example 59A syntheticoil 24A +53 −8 225 Example 60A synthetic oil 25A +45 +15 276 Comparativecomparative oil 7A separated separated 181 Example 26A throughoutthroughout the whole range the whole range Comparative comparative oil8A separated separated 114 Example 27A throughout throughout solidifiedthe whole range the whole range at room temperature Comparativecomparative oil 9A Separated separated 228 Example 28A throughoutthroughout the whole range the whole range Comparative comparative oil10A Separated separated 116 Example 29A throughout throughout the wholerange the whole range Comparative comparative oil 16A separatedSeparated 226 Example 30A throughout throughout the whole range thewhole range

TABLE 7 Refrigerant R-32/small refrigerated facility (as refrigerationoil having kinematic viscosity at 40° C. of 22-50 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 61Asynthetic oil 26A +66  −8 27.8 Example 62A synthetic oil 27A +70 orhigher −30 24.8 Example 63A synthetic oil 28A +63  −5 42.7 Example 64Asynthetic oil 29A +70 or higher −50 or lower 25.7 Example 65A syntheticoil 30A +70 or higher −48 29.4 Example 66A synthetic oil 31A +70 orhigher −14 36.8 Example 67A synthetic oil 32A +70 or higher −50 or lower47.2 Example 68A synthetic oil 33A +70 or higher −41 37.3 Example 69Asynthetic oil 34A +70 or higher −39 22.4 Example 70A synthetic oil 35A+70 or higher −16 26.0 Comparative comparative oil 11A separatedseparated 44.3 Example 31A throughout throughout the whole range thewhole range Comparative comparative oil 12A +48 +27 34.1 Example 32AComparative comparative oil 13A +41 +25 40.5 Example 33A Comparativecomparative oil 14A +44 +32 36.4 Example 34A Comparative comparative oil17A +43 +24 30.3 Example 35A Comparative comparative oil 18A separatedseparated 33.8 Example 36A throughout throughout the whole range thewhole range Comparative comparative oil 19A separated separated 32.4Example 37A throughout throughout the whole range the whole range

Test Example 3A: With Respect to Solubility with R-410A and KinematicViscosity

The high-temperature-side two-layer separation temperature and thelow-temperature-side two-layer separation temperature were measured inthe same manners as in Test Example 1A, except that R-410A was used as ahydrofluorocarbon-based refrigerant. The results of the measurements andthe kinematic viscosities are both shown in Table 8 and Table 9.

TABLE 8 Refrigerant R-410A/air conditioner (as refrigeration oil havingkinematic viscosity at 40° C. of 50-100 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 71Asynthetic oil 1A +51 −35 69.7 Example 72A synthetic oil 2A +60 −50 66.9Example 73A synthetic oil 3A +65 −50 or lower 66.0 Example 74A syntheticoil 4A +70 or higher −50 64.5 Example 75A synthetic oil 5A +54 −41 97.8Example 76A synthetic oil 6A +53 −39 75.1 Example 77A synthetic oil 7A+64 −50 or lower 60.0 Example 78A synthetic oil 8A +70 or higher −50 orlower 66.1 Example 79A synthetic oil 9A +59 −42 64.4 Example 80Asynthetic oil 10A +66 −50 or lower 62.5 Example 81A synthetic oil 11A+52 −50 or lower 67.1 Example 82A synthetic oil 12A +48 −50 or lower69.0 Example 83A synthetic oil 13A +59 −50 or lower 61.8 Example 84Asynthetic oil 14A +57 −31 53.9 Example 85A synthetic oil 15A +52 −2270.0 Comparative comparative oil 3A separated separated 88.0 Example 38Athroughout throughout the whole range the whole range Comparativecomparative oil 5A +64 −50 or lower 54.0 Example 39A solidified at roomtemperature Comparative comparative oil 6A separated separated 70.4Example 40A throughout throughout the whole range the whole range

TABLE 9 Refrigerant R-410A/large refrigerated facility or airconditioner (as refrigeration oil having kinematic viscosity at 40° C.of 100-320 mm²/s) Properties High-temperature- Low-temperature- Exampleside two-layer side two-layer Kinematic Comparative separationseparation viscosity Example temperature temperature (40° C.) No. OilNo. ° C. ° C. mm²/s Example 86A synthetic oil 16A +47 −35 140 Example87A synthetic oil 17A +70 or higher −50 or lower 139 Example 88Asynthetic oil 18A +70 or higher −50 or lower 141 Example 89A syntheticoil 19A +70 or higher −50 or lower 124 Example 90A synthetic oil 20A +58−43 108 Example 91A synthetic oil 21A +53 −41 149 Example 92A syntheticoil 22A +50 −32 196 Example 93A synthetic oil 23A +70 or higher −50 orlower 164 Example 94A synthetic oil 24A +52 −50 or lower 225 Example 95Asynthetic oil 25A +43 −25 276 Comparative comparative oil 7A separatedseparated 181 Example 41A throughout throughout the whole range thewhole range Comparative comparative oil 8A +27  +7 114 Example 42Asolidified at room temperature Comparative comparative oil 9A separatedseparated 228 Example 43A throughout throughout the whole range thewhole range Comparative comparative oil 10A separated separated 116Example 44A throughout throughout the whole range the whole range

Test Example 4A: With Respect to Solubility with HFO-1234yf andKinematic Viscosity

The high-temperature-side two-layer separation temperature and thelow-temperature-side two-layer separation temperature were measured inthe same manners as in Test Example 1A, except that HFO-1234yf was usedas a hydrofluorocarbon-based refrigerant. The results of themeasurements and the kinematic viscosities are both shown in Table 10 toTable 12.

TABLE 10 Refrigerant HFO-1234yf/air conditioner (as refrigeration oilhaving kinematic viscosity at 40° C. of 50-100 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 96Asynthetic oil 1A +70 or higher −50 or lower 69.7 Example 97A syntheticoil 2A +70 or higher −50 or lower 66.9 Example 98A synthetic oil 3A +70or higher −50 or lower 66.0 Example 99A synthetic oil 4A +70 or higher−50 or lower 64.5 Example 100A synthetic oil 5A +70 or higher −50 orlower 97.8 Example 101A synthetic oil 6A +70 or higher −50 or lower 75.1Example 102A synthetic oil 7A +70 or higher −50 or lower 60.0 Example103A synthetic oil 8A +70 or higher −50 or lower 66.1 Example 104Asynthetic oil 9A +70 or higher −50 or lower 64.4 Example 105A syntheticoil 10A +70 or higher −50 or lower 62.5 Example 106A synthetic oil 11A+70 or higher −50 or lower 67.1 Example 107A synthetic oil 12A +70 orhigher −50 or lower 69.0 Example 108A synthetic oil 13A +70 or higher−50 or lower 61.8 Example 109A synthetic oil 14A +70 or higher −50 orlower 53.9 Example 110A synthetic oil 15A +70 or higher −50 or lower70.0 Comparative comparative oil 4A +70 or higher −50 or lower 53.0Example 45A solidified at room temperature Comparative comparative oil5A +70 or higher −50 or lower 54.0 Example 46A solidified at roomtemperature

TABLE 11 Refrigerant HFO-1234yf/large refrigerated facility or airconditioner (as refrigeration oil having kinematic viscosity at 40° C.of 100-320 mm²/s) Properties High-temperature- Low-temperature- Exampleside two-layer side two-layer Kinematic Comparative separationseparation viscosity Example temperature temperature (40° C.) No. OilNo. ° C. ° C. mm²/s Example 111A synthetic oil 16A +70 or higher −50 orlower 140 Example 112A synthetic oil 17A +70 or higher −50 or lower 139Example 113A synthetic oil 18A +70 or higher −50 or lower 141 Example114A synthetic oil 19A +70 or higher −50 or lower 124 Example 115Asynthetic oil 20A +70 or higher −50 or lower 108 Example 116A syntheticoil 21A +70 or higher −50 or lower 149 Example 117A synthetic oil 22A+70 or higher −50 or lower 196 Example 118A synthetic oil 23A +70 orhigher −50 or lower 164 Example 119A synthetic oil 24A +70 or higher −50or lower 225 Example 120A synthetic oil 25A +70 or higher −50 or lower276 Comparative comparative oil 8A separated separated 114 Example 47Athroughout throughout solidified the whole range the whole range at roomtemperature

TABLE 12 Refrigerant HFO-1234yf/small refrigerated facility (asrefrigeration oil having kinematic viscosity at 40° C. of 22-50 mm²/s)Properties High-temperature- Low-temperature- Example side two-layerside two-layer Kinematic Comparative separation separation viscosityExample temperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/sExample 121A synthetic oil 26A +70 or higher −50 or lower 27.8 Example122A synthetic oil 27A +70 or higher −50 or lower 24.8 Example 123Asynthetic oil 28A +70 or higher −50 or lower 42.7 Example 124A syntheticoil 29A +70 or higher −50 or lower 25.7 Example 125A synthetic oil 30A+70 or higher −50 or lower 29.4 Example 126A synthetic oil 31A +70 orhigher −50 or lower 36.8 Example 127A synthetic oil 32A +70 or higher−50 or lower 47.2 Example 128A synthetic oil 33A +70 or higher −50 orlower 37.3 Example 129A synthetic oil 34A +70 or higher −50 or lower22.4 Example 130A synthetic oil 35A +70 or higher −50 or lower 26.0Comparative comparative oil 11A +70 or higher −50 or lower 17.2 Example48A Comparative comparative oil 12A +70 or higher −50 or lower 19.7Example 49A Comparative comparative oil 13A +70 or higher −50 or lower18.8 Example 50A

Test Example 5A: With Respect to Solubility with HFO-1234ze(E) andKinematic Viscosity

The high-temperature-side two-layer separation temperature and thelow-temperature-side two-layer separation temperature were measured inthe same manners as in Test Example 1A, except that HFO-1234ze(E) wasused as a hydrofluorocarbon-based refrigerant. The results of themeasurements and the kinematic viscosities are both shown in Table 13 toTable 15.

TABLE 13 Refrigerant HFO-1234ze(E)/air conditioner (as refrigeration oilhaving kinematic viscosity at 40° C. of 50-100 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example131A synthetic oil 1A +70 or higher −50 or lower 69.7 Example 132Asynthetic oil 2A +70 or higher −50 or lower 66.9 Example 133A syntheticoil 3A +70 or higher −50 or lower 66.0 Example 134A synthetic oil 4A +70or higher −50 or lower 64.5 Example 135A synthetic oil 5A +70 or higher−50 or lower 97.8 Example 136A synthetic oil 6A +70 or higher −50 orlower 75.1 Example 137A synthetic oil 7A +70 or higher −50 or lower 60.0Example 138A synthetic oil 8A +70 or higher −50 or lower 66.1 Example139A synthetic oil 9A +70 or higher −50 or lower 64.4 Example 140Asynthetic oil 10A +70 or higher −50 or lower 62.5 Example 141A syntheticoil 11A +70 or higher −50 or lower 67.1 Example 142A synthetic oil 12A+70 or higher −50 or lower 69.0 Example 143A synthetic oil 13A +70 orhigher −50 or lower 61.8 Example 144A synthetic oil 14A +70 or higher−50 or lower 53.9 Example 145A synthetic oil 15A +70 or higher −50 orlower 70.0 Comparative comparative oil 4A +70 or higher −50 or lower53.0 Example 51A solidified at room temperature Comparative comparativeoil 5A +70 or higher −50 or lower 54.0 Example 52A solidified at roomtemperature

TABLE 14 Refrigerant HFO-1234ze(E)/large refrigerated facility or airconditioner (as refrigeration oil having kinematic viscosity at 40° C.of 100-320 mm²/s) Properties High-temperature- Low-temperature- Exampleside two-layer side two-layer Kinematic Comparative separationseparation viscosity Example temperature temperature (40° C.) No. OilNo. ° C. ° C. mm²/s Example 146A synthetic oil 16A +70 or higher −50 orlower 140 Example 147A synthetic oil 17A +70 or higher −50 or lower 139Example 148A synthetic oil 18A +70 or higher −50 or lower 141 Example149A synthetic oil 19A +70 or higher −50 or lower 124 Example 150Asynthetic oil 20A +70 or higher −50 or lower 108 Example 151A syntheticoil 21A +70 or higher −50 or lower 149 Example 152A synthetic oil 22A+70 or higher −50 or lower 196 Example 153A synthetic oil 23A +70 orhigher −50 or lower 164 Example 154A synthetic oil 24A +70 or higher −50or lower 225 Example 155A synthetic oil 25A +70 or higher −50 or lower276 Comparative comparative oil 8A separated separated 114 Example 53Athroughout throughout solidified the whole range the whole range at roomtemperature

TABLE 15 Refrigerant HFO-1234ze(E)/small refrigerated facility (asrefrigeration oil having kinematic viscosity at 40° C. of 22-50 mm²/s)Properties High-temperature- Low-temperature- Example side two-layerside two-layer Kinematic Comparative separation separation viscosityExample temperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/sExample 156A synthetic oil 26A +70 or higher −50 or lower 27.8 Example157A synthetic oil 27A +70 or higher −50 or lower 24.8 Example 158Asynthetic oil 28A +70 or higher −50 or lower 42.7 Example 159A syntheticoil 29A +70 or higher −50 or lower 25.7 Example 160A synthetic oil 30A+70 or higher −50 or lower 29.4 Example 161A synthetic oil 31A +70 orhigher −50 or lower 36.8 Example 162A synthetic oil 32A +70 or higher−50 or lower 47.2 Example 163A synthetic oil 33A +70 or higher −50 orlower 37.3 Example 164A synthetic oil 34A +70 or higher −50 or lower22.4 Example 165A synthetic oil 35A +70 or higher −50 or lower 26.0Comparative comparative oil 11A +70 or higher −50 or lower 17.2 Example54A Comparative comparative oil 12A +70 or higher −50 or lower 19.7Example 55A Comparative comparative oil 13A +70 or higher −50 or lower18.8 Example 56A

Test Example 6A: With Respect to Lubricity of Refrigeration Oils

Examples 1A, 2A, 3A, 4A, and 8A and Comparative Example 1A, which is acurrent refrigeration oil for R-410A air conditioners, were evaluatedwith a Falex tester. The results thereof are shown in Table 16.

(Test Conditions)

-   -   Test apparatus: Falex tester (PIN-VEE BLOCK)    -   Test temperature: 80° C.    -   Test load: 150 lbs    -   Test period: 4 hr    -   Rotation speed: 290 rpm

TABLE 16 Example/Comparative Example No. Comparative Example ExampleExample Example Example Example 166A 167A 168A 169A 170A 57A Oil No.synthetic synthetic synthetic synthetic synthetic comparative oil 1A oil2A oil 3A oil 4A oil 8A oil 1A 2EHx molar 1 0.5 0.32 0.15 0 0.52 ratioDiPE molar 0.34 0.44 0.46 0.45 0.5 0 ratio Average 766 700 670 632 615668 molecular weight Wear ratio 0.61 0.92 0.63 0.98 0.51 1 (ComparativeExample 1A (current oil) being taken as 1)

Test Example 7A: With Respect to Hygroscopicity

Example 2A and Comparative Example 1A, which is a current refrigerationoil for R-410A air conditioners, were evaluated through a hygroscopicitytest. The results thereof are shown in Table 17.

(Test Conditions)

Test apparatus: A hygroscopicity tester based on a combination of ahumidifier, acrylic case, turntable, fan, heater, hygrometer, andthermometer was produced and used.

Test temperature: 30° C.

Test humidity: 80% RH

Surface area of specimen: 21.2 cm²

TABLE 17 Comparative Example 171A/ Example 171A Example 58A ComparativeTest Synthetic oil 2A Comparative oil 1A Example 58A period, moisturecontent, moisture Moisture hr ppm content, ppm content ratio 0 24 221.09 1 148 174 0.85 2 261 350 0.74 3 334 500 0.67 4 431 640 0.67 6 605790 0.77 8 780 921 0.85 10 932 1030 0.90 15 1200 1180 1.02 26 1587 13361.19 48 2150 1459 1.47 72 2296 1580 1.52 96 2523 1622 1.55

The open time which was supposed when facility dealers handledrefrigeration oils was set at 0.5 to 3 hours among the test periodsshown in Table 17, and refrigeration oils were compared in the degree ofmoisture absorption in a range including shorter and longer periods. Theresults thereof are shown in FIG. 1.

Test Example 8A: With Respect to Hydrolytic Resistance

A polyol ester oil which had a moisture content of 500 ppm and to whichan antioxidant and an acid scavenger had been added as additives wasenclosed in a glass tube together with refrigerant R-32 and an ironwire, copper wire, or aluminum wire as a catalyst, and a heating testwas conducted for 14 days in a 175° C. thermostatic chamber. Aftercompletion of the heating period, the contents were examined forappearance, color, any change in the catalyst, and precipitate.Furthermore, the polyol ester oil which had undergone the test was takenout and examined for acid value. The results thereof are shown in Table18 and Table 19.

TABLE 18 Example/Comparative Example No. Example Example Example ExampleExample Example 172A 173A 174A 175A 176A 177A Oil No. syntheticsynthetic synthetic synthetic synthetic synthetic oil 1A oil 2A oil 3Aoil 4A oil 5A oil 6A Appearance transparent transparent transparenttransparent transparent transparent Color (ASTM) L 0.5 L 0.5 L 0.5 L 0.5L 0.5 L 0.5 Change of catalyst, light light light light light light ironbrown brown brown brown brown brown Change of catalyst, no no no no nono copper change change change change change change Change of catalyst,no no no no no no aluminum change change change change change changePrecipitate none none none none none none Acid value, 0.04 0.04 0.040.05 0.04 0.04 mg-KOH/g

TABLE 19 Example/Comparative Example No. Comparative Comparative ExampleExample Example Example Example Example 178A 179A 180A 181A 59A 60A OilNo. synthetic synthetic synthetic synthetic comparative comparative oil7A oil 8A oil 9A oil 10A oil 1A oil 15A Appearance transparenttransparent transparent transparent transparent transparent Color (ASTM)L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Change of catalyst, light lightlight light light light iron brown brown brown brown brown brown Changeof catalyst, no no no no no no copper change change change change changechange Change of catalyst, no no no no no no aluminum change changechange change change change Precipitate none none none none none noneAcid value, 0.04 0.04 0.04 0.05 0.04 0.05 mg-KOH/g Note 1) Comparativeoil 1A and comparative oil 15A are in use in air conditioners whereR-410A, which is a current refrigerant, is used.

Test Example 9A: With Respect to Other Properties

Density, color, flash point, pour point, kinematic viscosity, viscosityindex, and total acid number, as properties required of refrigerationoils, are shown in Table 20 to Table 24 on the basis of Examples andComparative Examples.

TABLE 20 (as refrigeration oil having kinematic viscosity at 40° C. of50-100 mm²/s) Example/Comparative Example No. Example Example ExampleExample Example 182A 183A 184A 185A 186A Oil No. synthetic syntheticsynthetic synthetic synthetic oil 1A oil 2A oil 3A oil 4A oil 5ADensity, 15° C. 0.99 1.00 1.01 1.02 1.00 g/cm³ Color (ASTM) L 0.5 L 0.5L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250 or higher 250or higher 250 or higher 250 or higher Pour point, ° C. −35 −37.5 −40−42.5 −35 Kinematic viscosity, 40° C. 69.7 66.9 66.0 64.5 97.8 mm²/sKinematic viscosity, 100° C. 8.67 8.42 8.39 8.20 10.9 mm²/s Viscosityindex 95 94 95 95 96 Moisture content, ppm 25 25 25 25 25 Total acidnumber, 0.01 0.01 0.01 0.01 0.01 mg-KOH/g

TABLE 21 (as refrigeration oil having kinematic viscosity at 40° C. of50-100 mm²/s) Example/Comparative Example No. Example Example ExampleExample Example 187A 188A 189A 190A 191A Oil No. synthetic syntheticsynthetic synthetic synthetic oil 6A oil 7A oil 8A oil 9A oil 10ADensity, 15° C. 1.02 0.98 1.03 0.97 1.00 g/cm³ Color (ASTM) L 0.5 L 0.5L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250 or higher 250or higher 250 or higher 250 or higher Pour point, ° C. −35 −40 −37.5 −40−35 Kinematic viscosity, 40° C. 75.1 60.0 66.1 64.4 62.5 mm²/s Kinematicviscosity, 9.10 7.76 8.23 8.20 7.98 100° C. mm²/s Viscosity index 94 9191 91 92 Moisture content, ppm 25 25 25 25 25 Total acid number, 0.010.01 0.01 0.01 0.01 mg-KOH/g

TABLE 22 (as refrigeration oil having kinematic viscosity at 40° C. of50-100 mm²/s) Example/Comparative Example No. Comparative ExampleExample Example Example Example 192A 193A 194A 195A 61A Oil No.synthetic synthetic synthetic synthetic comparative oil 11A oil 12A oil13A oil 15A oil 1A Density, 15° C. 1.03 1.01 0.98 1.03 0.959 g/cm³ Color(ASTM) L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 orhigher 250 or higher 250 or higher 250 or higher 250 or higher Pourpoint, ° C. −47.5 −42.5 −42.5 −35 −40 Kinematic viscosity, 40° C. 67.169.0 61.8 70.0 67.8 mm²/s Kinematic viscosity, 100° C. 9.88 9.26 8.716.99 8.34 mm²/s Viscosity index 130 111 115 61 90 Moisture content, ppm25 25 25 25 25 Total acid number, 0.01 0.01 0.01 0.01 0.01 mg-KOH/gNote 1) Comparative oil 1A is a polyol ester in use in air conditionerswhere R-410A, which is a current refrigerant, is used.

TABLE 23 (as refrigeration oil having kinematic viscosity at 40° C. of100-320 mm²/s) Example/Comparative Example No. Comparative ExampleExample Example Example Example 196A 197A 198A 199A 62A Oil No.synthetic synthetic synthetic synthetic comparative oil 16A oil 17A oil24A oil 25A oil 16A Density, 15° C. 1.01 1.02 1.00 0.99 1.02 g/cm³ Color(ASTM) L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 orhigher 250 or higher 250 or higher 250 or higher 224 Pour point, ° C.−35 −37.5 −35 −35 −32.5 Kinematic viscosity, 40° C. 140 139 225 276 226mm²/s Kinematic viscosity, 100° C. 13.8 13.6 18.3 20.9 21.8 mm²/sViscosity index 94 93 89 89 116 Moisture content, ppm 25 25 25 25 25Total acid number, 0.01 0.01 0.01 0.01 0.01 mg-KOH/g Note 1) Comparativeoil 16A is a polyol ester in use in large refrigerated facilities or airconditioners where R-410A, R-134a, and the like, which are currentrefrigerants, are used.

TABLE 24 (as refrigeration oil having kinematic viscosity at 40° C. of22-50 mm²/s) Example/Comparative Example No. Compartive Example ExampleExample Example Example 200A 201A 202A 203A 63A Oil No. syntheticsynthetic synthetic synthetic comparative oil 30A oil 31A oil 32A oil35A oil 17A Density, 15° C. 1.00 0.99 1.02 0.99 0.99 g/cm³ Color (ASTM)L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250or higher 250 or higher 250 or higher 250 or higher Pour point, ° C.−42.5 −40 −42.5 −45 −50 Kinematic viscosity, 40° C. 29.4 36.8 47.3 26.030.3 mm²/s Kinematic viscosity, 100° C. 4.83 5.47 6.48 4.67 5.73 mm²/sViscosity index 76 76 82 93 133 Moisture content, ppm 25 25 25 25 50Total acid number, 0.01 0.01 0.01 0.01 0.02 mg-KOH/g Note 1) Comparativeoil 17A is a polyol ester in use in small refrigerated facilities whereR-134a, R-404A, and the like, which are current refrigerants, are used.(List of Polyol Ester Oils for Each Raw Material Combination)

The Examples and the Comparative Examples are arranged with respect toeach of raw material combinations to show that various viscosities andsolubility with various refrigerants are obtained by changing the ratioof raw materials. The relationships between the raw material combinationand kinematic viscosity or refrigerated facilities/air conditioners towhich the oil is applicable are as shown in the following Table 25 toTable 34.

TABLE 25 Raw material combination (1): alcohols, PE and DiPE; acid 1,2MBu; acid 2, 2EHx Kinematic viscosity Refrigerating Oil No. PE DiPE2MBu 2EHx (40° C.) mm²/s apparatus Synthetic 0.60 0.40 0.4 0.6 69.7 airconditioner oil 1A Synthetic 0.55 0.45 0.5 0.5 66.9 air conditioner oil2A Synthetic 0.55 0.45 0.7 0.3 66.0 air conditioner oil 3A Synthetic0.55 0.45 0.85 0.15 64.5 air conditioner oil 4A Synthetic 0.30 0.70 0.50.5 97.8 air conditioner oil 5A Synthetic 0.55 0.45 0.45 0.55 75.1 airconditioner oil 6A Synthetic 0.0 1.0 0.5 0.5 140 large refrigeratedfacility or oil 16A air conditioner Synthetic 0.0 1.0 0.65 0.35 139large refrigerated facility oil 17A or air conditioner Synthetic 0.0 1.01.0 0.0 141 large refrigerated facility oil 18A or air conditionerSynthetic 0.10 0.90 1.0 0.0 124 large refrigerated facility oil 19A orair conditioner Synthetic 1.0 0.0 1.0 0.0 25.7 small refrigeratedfacility oil 29A Synthetic 1.0 0.0 0.75 0.25 29.4 small refrigeratedfacility oil 30A Synthetic 1.0 0.0 0.5 0.5 36.8 small refrigeratedfacility oil 31A Synthetic 0.70 0.30 0.85 0.15 47.2 small refrigeratedfacility oil 32A Comparative 0.65 0.35 0.0 1.0 70.4 — oil 6A Comparative1.0 0.0 0.0 1.0 44.3 — oil 11A

TABLE 26 Raw material combination (2): alcohols, PE and DiPE; acid 1,2MBu; acid 2, TMHx Kinematic viscosity Refrigerating Oil No. PE DiPE2MBu TMHx (40° C.) mm²/s apparatus Synthetic 1.0 0.0 0.5 0.5 60.0 airconditioner oil 7A Synthetic 0.50 0.50 1.0 0.0 66.1 air conditioner oil8A Synthetic 1.0 0.0 0.4 0.6 64.4 air conditioner oil 9A Synthetic 0.850.15 0.6 0.4 62.5 air conditioner oil 10A Synthetic 0.0 1.0 1.0 0.0 141large refrigerated facility oil 18A or air conditioner Synthetic 0.100.90 1.0 0.0 124 large refrigerated facility oil 19A or air conditionerSynthetic 0.70 0.30 0.5 0.5 108 large refrigerated facility oil 20A orair conditioner Synthetic 0.50 0.50 0.5 0.5 149 large refrigeratedfacility oil 21A or air conditioner Synthetic 0.30 0.70 0.5 0.5 196large refrigerated facility oil 22A or air conditioner Synthetic 0.0 1.00.9 0.1 164 large refrigerated facility oil 23A or air conditionerSynthetic 0.0 1.0 0.65 0.35 225 large refrigerated facility oil 24A orair conditioner Synthetic 0.0 1.0 0.5 0.5 276 large refrigeratedfacility oil 25A or air conditioner Synthetic 1.0 0.0 1.0 0.0 25.7 smallrefrigerated facility oil 29A Synthetic 1.0 0.0 0.75 0.25 37.3 smallrefrigerated facility oil 33A Comparative 1.0 0.0 0.0 1.0 114 — oil 8Asolidified at room temperature

TABLE 27 Raw material combination (3): alcohols, PE and DiPE; acid 1,LPt; acid 2, 2EHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE LPt 2EHx mm²/s apparatus Synthetic 1.0 0.0 0.5 0.5 27.8 smallrefrigerated oil 26A facility Comparative 0.65 0.35 0.0 1.0 70.4 — oil6A Comparative 1.0 0.0 0.0 1.0 44.3 — oil 11A Comparative 1.0 0.0 0.250.75 34.1 — oil 12A

TABLE 28 Raw material combination (4): alcohols, PE and DiPE; acid 1,LPt; acid 2, TMHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE LPt TMHx mm²/s apparatus Synthetic 0.0 1.0 0.8 0.2 67.1 airconditioner oil 11A Synthetic 1.0 0.0 0.75 0.25 24.8 small refrigeratedoil 27A facility Synthetic 1.0 0.0 0.5 0.5 42.7 small refrigerated oil28A facility Comparative 1.0 0.0 0.0 1.0 114 — oil 8A solidified at roomtemper- ature

TABLE 29 Raw material combination (5): alcohols, PE and DiPE; acid 1,2MPt; acid 2, 2EHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE 2MPt 2EHx mm²/s apparatus Synthetic 0.25 0.75 0.8 0.2 69.0 airconditioner oil 12A Synthetic 0.25 0.75 1.0 0.0 61.8 air conditioner oil13A Synthetic 1.0 0.0 1.0 0.0 22.4 small refrigerated oil 34A facilitySynthetic 1.0 0.0 0.75 0.25 26.0 small refrigerated oil 35A facilityComparative 0.65 0.35 0.0 1.0 70.4 — oil 6A Comparative 0.0 1.0 0.350.65 116 — oil 10A Comparative 1.0 0.0 0.0 1.0 44.3 — oil 11AComparative 1.0 0.0 0.25 0.75 36.4 — oil 14A

TABLE 30 Raw material combination (6): alcohols, PE and DiPE; acid 1,2MPt; acid 2, TMHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE 2MPt TMHx mm²/s apparatus Synthetic 0.25 0.75 1.0 0.0 61.8 airconditioner oil 13A Synthetic 1.0 0.0 0.5 0.5 53.9 air conditioner oil14A Synthetic 1.0 0.0 1.0 0.0 22.4 small oil 34A refrigerated facilityComparative 1.0 0.0 0.0 1.0 114 — oil 8A solidified at room temper-ature

TABLE 31 Raw material combination (7): alcohols, PE and DiPE; acid 1,2EBu; acid 2, TMHx Kinematic viscosity Refrigerating Oil No. PE DiPE2EBu TMHx (40° C.) mm²/s apparatus Synthetic 1.0 0.0 0.75 0.25 70.0 airoil 15A conditioner Comparative 1.0 0.0 0.0 1.0 114 — oil 8A solidifiedat room temperature

TABLE 32 Raw material combination (8): alcohols, PE and DiPE; acid 1,LHx; acid 2, TMHx Kinematic viscosity Refrigerating Oil No. PE DiPE LHxTMHx (40° C.) mm²/s apparatus Comparative 1.0 0.0 0.25 0.75 64.6 — oil2A Comparative 0.0 1.0 0.65 0.35 88.0 — oil 3A Comparative 0.0 1.0 1.00.0 53.0 — oil 4A solidified at room temperature Comparative 0.0 1.00.35 0.65 181 — oil 7A Comparative 1.0 0.0 0.0 1.0 114 — oil 8Asolidified at room temperature Comparative 1.0 0.0 0.5 0.5 40.5 — oil13A

TABLE 33 Raw material combination (9): alcohols, PE and DiPE; acid 1,2EHx; acid 2, TMHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE 2EHx TMHx mm²/s apparatus Comparative 1.0 0.0 0.5 0.5 67.8 air oil1A conditioner Comparative 0.65 0.35 1.0 0.0 70.4 — oil 6A Comparative1.0 0.0 0.0 1.0 114 — oil 8A solidified at room temperature Comparative0.0 1.0 0.5 0.5 228 — oil 9A Comparative 1.0 0.0 1.0 0.0 44.3 — oil 11A

TABLE 34 Other combinations (conventional refrigeration oils) Kinematicviscosity (40° C.) Refrigerating Oil No. PE DiPE Acids mm²/s apparatusComparative 0.8 0.2 LPt: 0.4 30.3 small oil 17A n-heptanoic acid:refrigerated 0.4 facility MHx: 0.2 Comparative refrigerant R-410A/etheroil 64.7 air oil 15A for air conditioner conditioner Comparative complexester obtained from 226 large oil 16A PE, 2EHx, adipic acid, etc.refrigerated facility or air conditioner Refrigerating Alcohol:neopentyl glycol 7.56 domestic machine Fatty acid: 2EHx refrigerator oilA

The relationship between each raw material combination and thesolubility with each refrigerant (low-temperature-side two-layerseparation temperature) is as shown in the following Table 35 to Table44.

TABLE 35 Alcohols, PE and DiPE; acid 1, 2MBu; acid 2, 2EHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. HFO- Oil No. PE DiPE 2MBu 2EHx R-32 R-410A 1234ze(E)Synthetic 0.60 0.40 0.4 0.6 +16 −35 −50 or lower oil 1A Synthetic 0.550.45 0.5 0.5  −6 −50 −50 or lower oil 2A Synthetic 0.55 0.45 0.7 0.3 −30−50 or lower −50 or lower oil 3A Synthetic 0.55 0.45 0.85 0.15 −50 −50−50 or lower oil 4A Synthetic 0.30 0.70 0.5 0.5  +4 −41 −50 or lower oil5A Synthetic 0.55 0.45 0.45 0.55  +9 −39 −50 or lower oil 6A Synthetic0.0 1.0 0.5 0.5 +10 −35 −50 or lower oil 16A Synthetic 0.0 1.0 0.65 0.35−14 −50 or lower −50 or lower oil 17A Synthetic 0.0 1.0 1.0 0.0 −50 orlower −50 or lower −50 or lower oil 18A Synthetic 0.10 0.90 1.0 0.0 −50or lower −50 or lower −50 or lower oil 19A Synthetic 1.0 0.0 1.0 0.0 −50or lower −50 or lower −50 or lower oil 29A Synthetic 1.0 0.0 0.75 0.25−48 −50 or lower −50 or lower oil 30A Synthetic 1.0 0.0 0.5 0.5 −14 −50or lower −50 or lower oil 31A Synthetic 0.70 0.30 0.85 0.15 −50 or lower−50 or lower −50 or lower oil 32A Comparative 0.65 0.35 0.0 1.0separated separated −50 or lower oil 6A throughout throughout the wholethe whole range range Comparative 1.0 0.0 0.0 1.0 separated +17 −50 orlower oil 11A throughout the whole range

TABLE 36 Alcohols, PE and DiPE; acid 1, 2MBu; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. HFO- Oil No. PE DiPE 2MBu TMHx R-32 R-410A 1234ze(E)Synthetic 1.0 0.0 0.5 0.5 −13  −50 or lower −50 or lower oil 7ASynthetic 0.50 0.50 1.0 0.0 −50 or lower −50 or lower −50 or lower oil8A Synthetic 1.0 0.0 0.4 0.6 −2 −42 −50 or lower oil 9A Synthetic 0.850.15 0.6 0.4 −24  −50 or lower −50 or lower oil 10A Synthetic 0.0 1.01.0 0.0 −50 or lower −50 or lower −50 or lower oil 18A Synthetic 0.100.90 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 19A Synthetic0.70 0.30 0.5 0.5 −3 −43 −50 or lower oil 20A Synthetic 0.50 0.50 0.50.5 −1 −41 −50 or lower oil 21A Synthetic 0.30 0.70 0.5 0.5 +8 −32 −50or lower oil 22A Synthetic 0.0 1.0 0.9 0.1 −50 or lower −50 or lower −50or lower oil 23A Synthetic 0.0 1.0 0.65 0.35 −2 −50 or lower −50 orlower oil 24A Synthetic 0.0 1.0 0.5 0.5 +15  −25 −50 or lower oil 25ASynthetic 1.0 0.0 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 29ASynthetic 1.0 0.0 0.75 0.25 −30  −50 or lower −50 or lower oil 33AComparative 1.0 0.0 0.0 1.0 separated +7 −50 or lower oil 8A throughoutthe whole range

TABLE 37 Alcohols, PE and DiPE; acid 1, LPt; acid 2, 2EHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE LPt 2EHx R-32 R-410A HFO-1234ze(E) Synthetic1.0 0.0 0.5 0.5  −8 −49 −50 or lower oil 26A Comparative 0.65 0.35 0.01.0 separated separated −50 or lower oil 6A throughout throughout thewhole the whole range range Comparative 1.0 0.0 0.0 1.0 separated +17−50 or lower oil 11A throughout the whole range Comparative oil 1.0 0.00.25 0.75 +27 −20 −50 or lower 12A

TABLE 38 Alcohols, PE and DiPE; acid 1, LPt; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE LPt TMHx R-32 R-410A HFO-1234ze(E) Synthetic0.0 1.0 0.8 0.2 −12 −50 or lower −50 or lower oil 11A Synthetic 1.0 0.00.75 0.25 −30 −50 or lower −50 or lower oil 27A Synthetic 1.0 0.0 0.50.5  −5 −44 −50 or lower oil 28A Comparative 1.0 0.0 0.0 1.0 separated +7 −50 or lower oil 8A throughout the whole range

TABLE 39 Alcohols, PE and DiPE; acid 1, 2MPt; acid 2, 2EHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2MPt 2EHx R-32 R-410A HFO-1234ze(E) Synthetic0.25 0.75 0.8 0.2  −1 −50 or lower −50 or lower oil 12A Synthetic 0.250.75 1.0 0.0 −18 −50 or lower −50 or lower oil 13A Synthetic 1.0 0.0 1.00.0 −34 −50 or lower −50 or lower oil 34A Synthetic 1.0 0.0 0.75 0.25−16 −50 or lower −50 or lower oil 35A Comparative 0.65 0.35 0.0 1.0separated Separated −50 or lower oil 6A throughout throughout the wholethe whole range range Comparative 0.0 1.0 0.35 0.65 separated separated−50 or lower oil 10A throughout throughout the whole the whole rangerange Comparative 1.0 0.0 0.0 1.0 separated +17 −50 or lower oil 11Athroughout the whole range Comparative 1.0 0.0 0.25 0.75 +32 −19 −50 orlower oil 14A

TABLE 40 Alcohols, PE and DiPE; acid 1, 2MPt; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2MPt 2EHx R-32 R-410A HFO-1234ze(E) Synthetic0.25 0.75 1.0 0.0 −18 −50 or lower −50 or lower oil 13A Synthetic 1.00.0 0.5 0.5  +7 −31 −50 or lower oil 14A Synthetic 1.0 0.0 1.0 0.0 −34−50 or lower −50 or lower oil 34A Comparative 1.0 0.0 0.0 1.0 separated +7 −50 or lower oil 8A throughout the whole range

TABLE 41 Alcohols, PE and DiPE; acid 1, 2EBu; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2EBu TMHx R-32 R-410A HFO-1234ze(E) Synthetic1.0 0.0 0.75 0.25 +10 −22 −50 or lower oil 15A Comparative 1.0 0.0 0.01.0 separated +7 −50 or lower oil 8A throughout the whole range

TABLE 42 Alcohols, PE and DiPE; acid 1, LHx; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE LHx TMHx R-32 R-410A HFO-1234ze(E)Comparative 1.0 0.0 0.25 0.75 separated −8 −50 or lower oil 2Athroughout the whole range Comparative 0.0 1.0 0.65 0.35 separatedseparated −50 or lower oil 3A throughout throughout the whole the wholerange range Comparative 0.0 1.0 0.35 0.65 separated separated −50 orlower oil 7A throughout throughout the whole the whole range rangeComparative 1.0 0.0 0.0 1.0 separated +7 −50 or lower oil 8A throughoutthe whole range Comparative 1.0 0.0 0.5 0.5 +25 −19  −50 or lower oil13A

TABLE 43 Alcohols, PE and DiPE; acid 1, 2EHx; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2EHx TMHx R-32 R-410A HFO-1234ze(E)Comparative 1.0 0.0 0.5 0.5 separated +8 −50 or lower oil 1A throughoutthe whole range Comparative 0.65 0.35 1.0 0.0 separated separated −50 orlower oil 6A throughout throughout the whole the whole range rangeComparative 1.0 0.0 0.0 1.0 separated +7 −50 or lower oil 8A throughoutthe whole range Comparative 0.0 1.0 0.5 0.5 separated separated −50 orlower oil 9A throughout throughout the whole the whole range rangeComparative 1.0 0.0 1.0 0.0 separated +17  −50 or lower oil 11Athroughout the whole range

TABLE 44 Other combinations Low-temperature-side two-layer separationtemperature (oil content, 20%), ° C. HFO- Oil No. PE DiPE Acids R-32R-410A 1234ze(E) Comparative 0.8 0.2 LPt: 0.4 +24 −23 −50 or lower oil17A n-heptanoic acid: 0.4 TMHx: 0.2 Comparative refrigerant R-410A/etheroil separated −51 −50 or lower oil 15A for air conditioner throughoutthe whole range Comparative complex ester obtained from Separated −44−50 or lower oil 16A PE, 2EHx, adipic acid, etc. throughoutRefrigerating Alcohol: neopentyl glycol −20 −50 or lower −50 or lowermachine Fatty acid: 2EHx oil A

As shown in Table 23 to Table 32, the polyol ester oils each produced byesterifying an alcohol ingredient obtained by mixing pentaerythritolwith dipentaerythritol and a fatty acid ingredient composed of at leastone of pentanoic acid and hexanoic acid and at least one of octanoicacid and nonanoic acid are made to have various values of viscosity bychanging the proportions of the raw materials with respect to each ofspecific raw material combinations.

Furthermore, as shown in Test Examples 1A to 4A and Table 33 to Table42, refrigeration oil compositions which are excellent in terms ofsolubility and lubricity can be produced by using polyol ester oils eachproduced by esterifying an alcohol ingredient obtained by mixingpentaerythritol with dipentaerythritol and a fatty acid ingredientcomposed of at least one of pentanoic acid and hexanoic acid and atleast one of octanoic acid and nonanoic acid, in accordance with thekinds of hydrofluorocarbon-based refrigerants. Moreover, as shown inTest Examples 5A to 8A, the polyol ester oils produced are equal orsuperior to conventional refrigeration oils in other performances and,by incorporating additives thereinto as in conventional products, thepolyol ester oils can be rendered usable also in refrigerated facilitiesemploying refrigerants having a low global warming potential, such asrefrigerant R-32, as in apparatus in which R-410A, a conventionalrefrigerant, is used.

<Test B: Refrigeration Oil Compositions for Hydrocarbon-BasedRefrigerants>

The alcohol ingredients and fatty acid ingredients shown in Table B wereesterified to produce polyol ester oils. In the table, PE representspentaerythritol, DiPE represents dipentaerythritol, LPt representsnormal pentanoic acid (a pentanoic acid), 2 MBu representsDL-2-methylbutanoic acid (a pentanoic acid), LHx represents normalhexanoic acid (a hexanoic acid), 2 MPt represents DL-2-methylpentanoicacid (a hexanoic acid), 2EBu represents 2-ethylbutanoic acid (a hexanoicacid), 2EHx represents a 2-ethylhexanoic acid (an octanoic acid), andTMHx represents 3,5,5-trimethylhexanoic acid (a nonanoic acid), and themixing proportion of each alcohol ingredient to the fatty acidingredient is in molar ratio. A mineral oil (comparative oil 15B) forrefrigerant R-290 was also used as a comparative oil.

TABLE B (Polyol ester oils used in Examples and Comparative Examples)Alcohol ingredient Fatty acid ingredient Oil No. PE DiPE Acid 1 Acid 2Synthetic oil 1B 0.60 0.40 2MBu: 0.4 2EHx: 0.6 Synthetic oil 2B 0.550.45 2MBu: 0.5 2EHx: 0.5 Synthetic oil 3B 0.55 0.45 2MBu: 0.7 2EHx: 0.3Synthetic oil 4B 0.55 0.45 2MBu: 0.85 2EHx: 0.15 Synthetic oil 5B 0.300.70 2MBu: 0.5 2EHx: 0.5 Synthetic oil 6B 0.55 0.45 2MBu: 0.45 2EHx:0.55 Synthetic oil 7B 1.0 0.0 2MBu: 0.5 TMHx: 0.5 Synthetic oil 8B 0.500.50 2MBu: 1.0 TMHx: 0.0 Synthetic oil 9B 1.0 0.0 2MBu: 0.4 TMHx: 0.6Synthetic oil 10B 0.85 0.15 2MBu: 0.6 TMHx: 0.4 Synthetic oil 11B 0.01.0 LPt: 0.8 TMHx: 0.2 Synthetic oil 12B 0.25 0.75 2MPt: 0.8 2EHx: 0.2Synthetic oil 13B 0.25 0.75 2MPt: 1.0 — Synthetic oil 14B 1.0 0.0 2MPt:0.5 TMHx: 0.5 Synthetic oil 15B 1.0 0.0 2EBu: 0.75 TMHx: 0.25 Syntheticoil 16B 0.0 1.0 2MBu: 0.5 2EHx: 0.5 Synthetic oil 17B 0.0 1.0 2MBu: 0.72EHx: 0.35 Synthetic oil 18B 0.0 1.0 2MBu: 1.0 — Synthetic oil 19B 0.100.90 2MBu: 1.0 — Synthetic oil 20B 0.70 0.30 2MBu: 0.5 TMHx: 0.5Synthetic oil 21B 0.50 0.50 2MBu: 0.5 TMHx: 0.5 Synthetic oil 22B 0.300.70 2MBu: 0.5 TMHx: 0.5 Synthetic oil 23B 0.0 1.0 2MBu: 0.9 TMHx: 0.1Synthetic oil 24B 0.0 1.0 2MBu: 0.7 TMHx: 0.3 Synthetic oil 25B 0.0 1.02MBu: 0.5 TMHx: 0.5 Synthetic oil 26B 1.0 0.0 LPt: 0.5 2EHx: 0.5Synthetic oil 27B 1.0 0.0 LPt: 0.75 TMHx: 0.25 Synthetic oil 28B 1.0 0.0LPt: 0.5 TMHx: 0.5 Synthetic oil 29B 1.0 0.0 2MBu: 1.0 — Synthetic oil30B 1.0 0.0 2MBu: 0.75 2EHx: 0.25 Synthetic oil 31B 1.0 0.0 2MBu: 0.52EHx: 0.5 Synthetic oil 32B 0.70 0.30 2MBu: 0.85 2EHx: 0.15 Syntheticoil 33B 1.0 0.0 2MBu: 0.75 TMHx: 0.25 Synthetic oil 34B 1.0 0.0 2MPt:1.0 — Synthetic oil 35B 1.0 0.0 2MPt: 0.75 2EHx: 0.25 Comparative oil 1B1.0 0.0 2EHx: 0.5 TMHx: 0.5 Comparative oil 2B 1.0 0.0 LHx: 0.25 TMHx:0.75 Comparative oil 3B 0.0 1.0 LHx: 0.65 TMHx: 0.35 Comparative oil 4B0.0 1.0 LHx: 1.0 — Comparative oil 5B 1.0 0.0 2EBu: 1.0 — Comparativeoil 6B 0.65 0.35 2EHx: 1.0 — Comparative oil 7B 0.0 1.0 LHx: 0.35 TMHx:0.65 Comparative oil 8B 1.0 0.0 TMHx: 1.0 — Comparative oil 9B 0.0 1.02EHx: 0.5 TMHx: 0.5 Comparative oil 10B 0.0 1.0 2MPt: 0.35 2EHx: 0.65Comparative oil 11B 1.0 0.0 2EHx: 1.0 — Comparative oil 12B 1.0 0.0 LPt:0.25 2EHx: 0.75 Comparative oil 13B 1.0 0.0 LHx: 0.5 TMHx: 0.5Comparative oil 14B 1.0 0.0 2MPt: 0.25 2EHx: 0.75 Comparative oil 15Brefrigerant R-290/mineral oil for air conditioner Comparative oil 16Bcomplex ester obtained from PE, 2EHx, adipic acid, etc. Comparative oil17B 0.8 0.2 LPt: 0.4 n-heptanoic acid: 0.4 TMHx: 0.2 Comparative oil 18Bmixed oil (refrigeration oil B, 25 wt % + comparative oil 1, 75 wt %)Makeup of refrigeration oil B Alcohol: neopentyl glycol Fatty acid: 2EHxComparative oil 19B mixed oil (refrigeration oil B, 50 wt % +comparative oil 9, 50 wt %) Makeup of refrigeration oil B Alcohol:neopentyl glycol Fatty acid: 2EHx Comparative oil 20 mixed oil(refrigeration oil B, 30 wt % + comparative oil 16, 70 wt %) Makeup ofrefrigeration oil B Alcohol: neopentyl glycol Fatty acid: 2EHx

Test Example 1B: With Respect to Kinematic Viscosities of Each PolyolEster Oil Synthesized

Each of the polyol ester oils and comparative oils was examined forkinematic viscosity at 40° C. and 100° C. The results of the measurementare shown in Tables 47 and 48.

TABLE 47 Kinematic viscosity mm²/ mm²/ Example No. Oil No. s (40° C.) s(100° C.) Remarks Example 1B synthetic oil 1B 69.7 8.67 — Example 2Bsynthetic oil 2B 66.9 8.42 — Example 3B synthetic oil 3B 66.0 8.39 —Example 4B synthetic oil 4B 64.5 8.20 — Example 5B synthetic oil 5B 97.810.9 — Example 6B synthetic oil 6B 75.1 9.10 — Example 7B synthetic oil7B 60.0 7.76 — Example 8B synthetic oil 8B 66.1 8.23 — Example 9Bsynthetic oil 9B 64.4 8.20 — Example 10B synthetic oil 10B 62.5 7.98 —Example 11B synthetic oil 11B 67.1 9.88 — Example 12B synthetic oil 12B69.0 9.26 — Example 13B synthetic oil 13B 61.8 8.71 — Example 14Bsynthetic oil 14B 53.9 7.39 — Example 15B synthetic oil 15B 70.0 6.99 —Example 16B synthetic oil 16B 140 13.8 — Example 17B synthetic oil 17B139 13.6 — Example 18B synthetic oil 18B 141 13.6 — Example 19Bsynthetic oil 19B 124 12.4 — Example 20B synthetic oil 20B 108 11.4 —Example 21B synthetic oil 21B 149 14.0 — Example 22B synthetic oil 22B196 16.7 — Example 23B synthetic oil 23B 164 15.0 — Example 24Bsynthetic oil 24B 225 18.3 — Example 25B synthetic oil 25B 276 20.9 —Example 26B synthetic oil 26B 27.8 4.99 — Example 27B synthetic oil 27B24.8 4.88 — Example 28B synthetic oil 28B 42.7 6.69 — Example 29Bsynthetic oil 29B 25.7 4.39 — Example 30B synthetic oil 30B 29.4 4.83 —Example 31B synthetic oil 31B 36.8 5.47 — Example 32B synthetic oil 32B47.3 6.48 — Example 33B synthetic oil 33B 37.3 5.66 — Example 34Bsynthetic oil 34B 22.4 4.31 — Example 35B synthetic oil 35B 26.0 4.67 —

TABLE 48 Kinematic viscosity Comparative mm²/s Example No. Oil No. mm²/s(40° C.) (100° C.) Remarks Comparative comparative 67.8 8.34 — Example1B oil 1B Comparative comparative 64.6 8.50 — Example 2B oil 2BComparative comparative 88.0 11.9 — Example 3B oil 3B Comparativecomparative 53.0 8.72 solidified at Example 4B oil 4B room temperatureComparative comparative 54.0 6.36 solidified at Example 5B oil 5B roomtemperature Comparative comparative 70.4 8.74 — Example 6B oil 6BComparative comparative 181 17.6 — Example 7B oil 7B Comparativecomparative 114 11.5 solidified at Example 8B oil 8B room temperatureComparative comparative 228 19.2 — Example 9B oil 9B Comparativecomparative 116 12.9 — Example 10B oil 10B Comparative comparative 44.36.26 — Example 11B oil 11B Comparative comparative 34.1 5.44 — Example12B oil 12B Comparative comparative 40.5 6.58 — Example 13B oil 13BComparative comparative 36.4 5.60 — Example 14B oil 14B Comparativecomparative 95.9 8.09 — Example 15B oil 15B Comparative comparative 22621.8 — Example 16B oil 16B Comparative comparative 30.3 5.73 — Example17B oil 17B Comparative comparative 33.8 5.44 — Example 18B oil 18BComparative comparative 32.4 5.42 — Example 19B oil 19B Comparativecomparative 67.4 9.42 — Example 20B oil 20B

Test 2B: With Respect to Solubility with R-290 and Kinematic Viscosity

Each polyol ester oil and R-290 were enclosed in a glass tube so as toresult in an oil content of 20% by weight, and the glass tube was shakento dissolve the R-290 in the polyol ester oil. After the dissolution,the glass tube was placed in a water bath and gradually heated tomeasure the temperature at which the even layer separated into an oillayer and a refrigerant layer (high-temperature-side two-layerseparation temperature). Meanwhile, the glass tube was placed in acooling chamber and gradually cooled to measure the temperature at whichthe even layer separated into an oil layer and a refrigerant layer(low-temperature-side two-layer separation temperature). The results ofthe measurements and the kinematic viscosities are both shown in Table49 to Table 51.

TABLE 49 Refrigerant R-290/air conditioner (as refrigeration oil havingkinematic viscosity at 40° C. of 50-100 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 36Bsynthetic oil 1B +70 or higher −50 or lower 69.7 Example 37B syntheticoil 2B +70 or higher −50 or lower 66.9 Example 38B synthetic oil 3B +70or higher −50 or lower 66.0 Example 39B synthetic oil 4B +70 or higher−50 or lower 64.5 Example 40B synthetic oil 5B +70 or higher −50 orlower 97.8 Example 41B synthetic oil 6B +70 or higher −50 or lower 75.1Example 42B synthetic oil 7B +70 or higher −50 or lower 60.0 Example 43Bsynthetic oil 8B +70 or higher −50 or lower 66.1 Example 44B syntheticoil 9B +70 or higher −50 or lower 64.4 Example 45B synthetic oil 10B +70or higher −50 or lower 62.5 Example 46B synthetic oil 11B +70 or higher−50 or lower 67.1 Example 47B synthetic oil 12B +70 or higher −50 orlower 69.0 Example 48B synthetic oil 13B +70 or higher −50 or lower 61.8Example 49B synthetic oil 14B +70 or higher −50 or lower 53.9 Example50B synthetic oil 15B +70 or higher −50 or lower 70.0 Comparativecomparative oil 4B +70 or higher −50 or lower 53.0 Example 21Bsolidified at room temperature Comparative comparative oil 5B +70 orhigher −50 or lower 54.0 Example 22B solidified at room temperature

TABLE 50 Refrigerant R-290/large refrigerated facility or airconditioner (as refrigeration oil having kinematic viscosity at 40° C.of 100-350 mm²/s) Properties High-temperature- Low-temperature- Exampleside two-layer side two-layer Kinematic Comparative separationseparation viscosity Example temperature temperature (40° C.) No. OilNo. ° C. ° C. mm²/s Example 51B synthetic oil 16B +70 or higher −50 orlower 140 Example 52B synthetic oil 17B +70 or higher −50 or lower 139Example 53B synthetic oil 18B +70 or higher −50 or lower 141 Example 54Bsynthetic oil 19B +70 or higher −50 or lower 124 Example 55B syntheticoil 20B +70 or higher −50 or lower 108 Example 56B synthetic oil 21B +70or higher −50 or lower 149 Example 57B synthetic oil 22B +70 or higher−50 or lower 196 Example 58B synthetic oil 23B +70 or higher −50 orlower 164 Example 59B synthetic oil 24B +70 or higher −50 or lower 225Example 60B synthetic oil 25B +70 or higher −50 or lower 276 Comparativecomparative oil 8B separated separated 114 Example 23B throughoutthroughout solidified the whole range the whole range at roomtemperature

TABLE 51 Refrigerant R-290/small refrigerated facility (as refrigerationoil having kinematic viscosity at 40° C. of 15-50 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 61Bsynthetic oil 26B +70 or higher −50 or lower 27.8 Example 62B syntheticoil 27B +70 or higher −50 or lower 24.8 Example 63B synthetic oil 28B+70 or higher −50 or lower 42.7 Example 64B synthetic oil 29B +70 orhigher −50 or lower 25.7 Example 65B synthetic oil 30B +70 or higher −50or lower 29.4 Example 66B synthetic oil 31B +70 or higher −50 or lower36.8 Example 67B synthetic oil 32B +70 or higher −50 or lower 47.2Example 68B synthetic oil 33B +70 or higher −50 or lower 37.3 Example69B synthetic oil 34B +70 or higher −50 or lower 22.4 Example 70Bsynthetic oil 35B +70 or higher −50 or lower 26.0

Test Example 3B: With Respect to Solubility with R-600a and KinematicViscosity

The high-temperature-side two-layer separation temperature and thelow-temperature-side two-layer separation temperature were measured inthe same manners as in Test Example 1B, except that R-600a was used as ahydrocarbon-based refrigerant. The results of the measurements and thekinematic viscosities are both shown in Table 52 and Table 53.

TABLE 52 Refrigerant R-600a/air conditioner (as refrigeration oil havingkinematic viscosity at 40° C. of 50-100 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 71Bsynthetic oil 1B +70 or higher −50 or lower 69.7 Example 72B syntheticoil 2B +70 or higher −50 or lower 66.9 Example 73B synthetic oil 3B +70or higher −50 or lower 66.0 Example 74B synthetic oil 4B +70 or higher−50 or lower 64.5 Example 75B synthetic oil 5B +70 or higher −50 orlower 97.8 Example 76B synthetic oil 6B +70 or higher −50 or lower 75.1Example 77B synthetic oil 7B +70 or higher −50 or lower 60.0 Example 78Bsynthetic oil 8B +70 or higher −50 or lower 66.1 Example 79B syntheticoil 9B +70 or higher −50 or lower 64.4 Example 80B synthetic oil 10B +70or higher −50 or lower 62.5 Example 81B synthetic oil 11B +70 or higher−50 or lower 67.1 Example 82B synthetic oil 12B +70 or higher −50 orlower 69.0 Example 83B synthetic oil 13B +70 or higher −50 or lower 61.8Example 84B synthetic oil 14B +70 or higher −50 or lower 53.9 Example85B synthetic oil 15B +70 or higher −50 or lower 70.0 Comparativecomparative oil 5B +70 or higher −50 or lower 54.0 Example 24Bsolidified at room temperature

TABLE 53 Refrigerant R-600a/large refrigerated facility or airconditioner (as refrigeration oil having kinematic viscosity at 40° C.of 100-350 mm²/s) Properties High-temperature- Low-temperature- Exampleside two-layer side two-layer Kinematic Comparative separationseparation viscosity Example temperature temperature (40° C.) No. OilNo. ° C. ° C. mm²/s Example 86B synthetic oil 16B +70 or higher −50 orlower 140 Example 87B synthetic oil 17B +70 or higher −50 or lower 139Example 88B synthetic oil 18B +70 or higher −50 or lower 141 Example 89Bsynthetic oil 19B +70 or higher −50 or lower 124 Example 90B syntheticoil 20B +70 or higher −50 or lower 108 Example 91B synthetic oil 21B +70or higher −50 or lower 149 Example 92B synthetic oil 22B +70 or higher−50 or lower 196 Example 93B synthetic oil 23B +70 or higher −50 orlower 164 Example 94B synthetic oil 24B +70 or higher −50 or lower 225Example 95B synthetic oil 25B +70 or higher −50 or lower 276 Comparativecomparative oil 8B +70 or higher −50 or lower 114 Example 25B solidifiedat room temperature

Test Example 4B: With Respect to Solubility with R-1270 and KinematicViscosity

The high-temperature-side two-layer separation temperature and thelow-temperature-side two-layer separation temperature were measured inthe same manners as in Test Example 1B, except that R-1270 was used as ahydrocarbon-based refrigerant. The results of the measurements and thekinematic viscosities are both shown in Table 54 to Table 56.

TABLE 54 Refrigerant R-1270/air conditioner (as refrigeration oil havingkinematic viscosity at 40° C. of 50-100 mm²/s) PropertiesHigh-temperature- Low-temperature- Example side two-layer side two-layerKinematic Comparative separation separation viscosity Exampletemperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/s Example 96Bsynthetic oil 1B +70 or higher −50 or lower 69.7 Example 97B syntheticoil 2B +70 or higher −50 or lower 66.9 Example 98B synthetic oil 3B +70or higher −50 or lower 66.0 Example 99B synthetic oil 4B +70 or higher−50 or lower 64.5 Example 100B synthetic oil 5B +70 or higher −50 orlower 97.8 Example 101B synthetic oil 6B +70 or higher −50 or lower 75.1Example 102B synthetic oil 7B +70 or higher −50 or lower 60.0 Example103B synthetic oil 8B +70 or higher −50 or lower 66.1 Example 104Bsynthetic oil 9B +70 or higher −50 or lower 64.4 Example 105B syntheticoil 10B +70 or higher −50 or lower 62.5 Example 106B synthetic oil 11B+70 or higher −50 or lower 67.1 Example 107B synthetic oil 12B +70 orhigher −50 or lower 69.0 Example 108B synthetic oil 13B +70 or higher−50 or lower 61.8 Example 109B synthetic oil 14B +70 or higher −50 orlower 53.9 Example 110B synthetic oil 15B +70 or higher −50 or lower70.0 Comparative comparative oil 4B +70 or higher −50 or lower 53.0Example 26B solidified at room temperature Comparative comparative oil5B +70 or higher −50 or lower 54.0 Example 27B solidified at roomtemperature

TABLE 55 Refrigerant R-1270/large refrigerated facility or airconditioner (as refrigeration oil having kinematic viscosity at 40° C.of 100-350 mm²/s) Properties High-temperature- Low-temperature- Exampleside two-layer side two-layer Kinematic Comparative separationseparation viscosity Example temperature temperature (40° C.) No. OilNo. ° C. ° C. mm²/s Example 111B synthetic oil 16B +70 or higher −50 orlower 140 Example 112B synthetic oil 17B +70 or higher −50 or lower 139Example 113B synthetic oil 18B +70 or higher −50 or lower 141 Example114B synthetic oil 19B +70 or higher −50 or lower 124 Example 115Bsynthetic oil 20B +70 or higher −50 or lower 108 Example 116B syntheticoil 21B +70 or higher −50 or lower 149 Example 117B synthetic oil 22B+70 or higher −50 or lower 196 Example 118B synthetic oil 23B +70 orhigher −50 or lower 164 Example 119B synthetic oil 24B +70 or higher −50or lower 225 Example 120B synthetic oil 25B +70 or higher −50 or lower276 Comparative comparative oil 8B separated separated 114 Example 28Bthroughout throughout solidified the whole range the whole range at roomtemperature

TABLE 56 Refrigerant R-1270/small refrigerated facility (asrefrigeration oil having kinematic viscosity at 40° C. of 15-50 mm²/s)Properties High-temperature- Low-temperature- Example side two-layerside two-layer Kinematic Comparative separation separation viscosityExample temperature temperature (40° C.) No. Oil No. ° C. ° C. mm²/sExample 121B synthetic oil 26B +70 or higher −50 or lower 27.8 Example122B synthetic oil 27B +70 or higher −50 or lower 24.8 Example 123Bsynthetic oil 28B +70 or higher −50 or lower 42.7 Example 124B syntheticoil 29B +70 or higher −50 or lower 25.7 Example 125B synthetic oil 30B+70 or higher −50 or lower 29.4 Example 126B synthetic oil 31B +70 orhigher −50 or lower 36.8 Example 127B synthetic oil 32B +70 or higher−50 or lower 47.2 Example 128B synthetic oil 33B +70 or higher −50 orlower 37.3 Example 129B synthetic oil 34B +70 or higher −50 or lower22.4 Example 130B synthetic oil 35B +70 or higher −50 or lower 26.0

Test Example 5B: With Respect to Lubricity of Refrigeration Oils

Examples 1B, 2B, 3B, 4B, and 8B and Comparative Example 1B wereevaluated with a Falex tester. The results thereof are shown in Table57.

(Test Conditions)

Test apparatus: Falex tester (PIN-VEE BLOCK)

Test temperature: 80° C.

Test load: 150 lbs

Test period: 4 hr

Rotation speed: 290 rpm

TABLE 57 Example/Comparative Example No. Comparative Example ExampleExample Example Example Example 131B 132B 133B 134B 135B 29B Oil No.synthetic synthetic synthetic synthetic synthetic comparative oil 1B oil2B oil 3B oil 4B oil 8B oil 1B 2EHx molar 1 0.5 0.32 0.15 0 0.52 ratioDiPE molar 0.34 0.44 0.46 0.45 0.5 0 ratio Average 766 700 670 632 615668 molecular weight Wear ratio 0.61 0.92 0.63 0.98 0.51 1 (Relativevalue, with Comparative Example 1B taken as 1)

Test Example 6B: With Respect to Hygroscopicity

Example 2B and Comparative Example 1B were evaluated through ahygroscopicity test. The results thereof are shown in Table 58.

(Test Conditions)

Test apparatus: A hygroscopicity tester based on a combination of ahumidifier, acrylic case, turntable, fan, heater, hygrometer, andthermometer was produced and used.

Test temperature: 30° C.

Test humidity: 80% RH

Surface area of specimen: 21.2 cm²

TABLE 58 Comparative Example 136B/ Example 136B Example 30B ComparativeTest Synthetic oil 2B Comparative oil 1B Example 30B period, moisturecontent, moisture content, Moisture hr ppm ppm content ratio 0 24 221.09 1 148 174 0.85 2 261 350 0.74 3 334 500 0.67 4 431 640 0.67 6 605790 0.77 8 780 921 0.85 10 932 1030 0.90 15 1200 1180 1.02 26 1587 13361.19 48 2150 1459 1.47 72 2296 1580 1.52 96 2523 1622 1.55

The open time which was supposed when facility dealers handledrefrigeration oils was set at 0.5 to 3 hours among the test periodsshown in Table 58, and refrigeration oils were compared in the degree ofmoisture absorption in a range including shorter and longer periods. Theresults thereof are shown in FIG. 2.

Test Example 7B: With Respect to Hydrolytic Resistance

A polyol ester oil which had a moisture content of 500 ppm and to whichan antioxidant and an acid scavenger had been added as additives wasenclosed in a glass tube together with refrigerant R-290 and an ironwire, copper wire, or aluminum wire as a catalyst, and a heating testwas conducted for 14 days in a 175° C. thermostatic chamber. Aftercompletion of the heating period, the contents were examined forappearance, color, any change in the catalyst, and precipitate.Furthermore, the polyol ester oil which had undergone the test was takenout and examined for acid value. The results thereof are shown in Table59 and Table 60.

TABLE 59 Example/Comparative Example No. Example Example Example ExampleExample Example 137B 138B 139B 140B 141B 142B Oil No. syntheticsynthetic synthetic synthetic synthetic synthetic oil 1B oil 2B oil 3Boil 4B oil 5B oil 6B Appearance transparent transparent transparenttransparent transparent transparent Color (ASTM) L 0.5 L 0.5 L 0.5 L 0.5L 0.5 L 0.5 Change of catalyst, light light light light light light ironbrown brown brown brown brown brown Change of catalyst, no no no no nono copper change change change change change change Change of catalyst,no no no no no no aluminum change change change change change changePrecipitate none none none none none none Acid value, 0.04 0.04 0.040.05 0.04 0.04 mg-KOH/g

TABLE 60 Example/Comparative Example No. Comparative Comparative ExampleExample Example Example Example Example 143B 144B 145B 146B 31B 32B OilNo. synthetic synthetic synthetic synthetic comparative comparative oil7B oil 8B oil 9B oil 10B oil 1B oil 15B Appearance transparenttransparent transparent transparent transparent transparent Color (ASTM)L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Change of catalyst, light lightlight light light light iron brown brown brown brown brown brown Changeof catalyst, no no no no no no copper change change change change changechange Change of catalyst, no no no no no no aluminum change changechange change change change Precipitate none none none none none noneAcid value, 0.04 0.04 0.04 0.05 0.04 0.01 mg-KOH/g

Test Example 8B: With Respect to Other Properties

Density, color, flash point, pour point, kinematic viscosity, viscosityindex, and total acid number, as properties required of refrigerationoils, are shown in Table 61 to Table 65 on the basis of Examples andComparative Examples.

TABLE 61 (as refrigeration oil having kinematic viscosity at 40° C. of50-100 mm²/s) Example/Comparative Example No. Example Example ExampleExample Example 147B 148B 149B 150B 151B Oil No. synthetic syntheticsynthetic synthetic synthetic oil 1B oil 2B oil 3B oil 4B oil 5BDensity, 15° C. 0.99 1.00 1.01 1.02 1.00 g/cm³ Color (ASTM) L 0.5 L 0.5L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250 or higher 250or higher 250 or higher 250 or higher Pour point, ° C. −35 −37.5 −40−42.5 −35 Kinematic viscosity, 40° C. 69.7 66.9 66.0 62.5 97.8 mm²/sKinematic viscosity, 100° C. 8.67 8.42 8.39 8.02 10.9 mm²/s Viscosityindex 95 94 95 93 96 Moisture content, ppm 25 25 25 25 25 Total acidnumber, 0.01 0.01 0.01 0.01 0.01 mg-KOH/g

TABLE 62 (as refrigeration oil having kinematic viscosity at 40° C. of50-100 mm²/s) Example/Comparative Example No. Example Example ExampleExample Example 152B 153B 154B 155B 156B Oil No. synthetic syntheticsynthetic synthetic synthetic oil 6B oil 7B oil 8B oil 9B oil 10BDensity, 15° C. 1.02 0.98 1.03 0.97 1.00 g/cm³ Color (ASTM) L 0.5 L 0.5L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250 or higher 250or higher 250 or higher 250 or higher Pour point, ° C. −35 −40 −37.5 −40−35 Kinematic viscosity, 40° C. 75.1 60.0 66.1 64.4 62.5 mm²/s Kinematicviscosity, 100° C. 9.10 7.75 8.23 8.20 8.34 mm²/s Viscosity index 94 9191 91 94 Moisture content, ppm 25 25 25 25 25 Total acid number, 0.010.01 0.01 0.01 0.01 mg-KOH/g

TABLE 63 (as refrigeration oil having kinematic viscosity at 40° C. of50-100 mm²/s) Example/Comparative Example No. Example Example ExampleExample Comparative 157B 158B 159B 160B Example 33B Oil No. syntheticsynthetic synthetic synthetic comparative oil 11B oil 12B oil 13B oil15B oil 1B Density, 15° C. 1.03 1.01 0.98 1.03 0.959 g/cm³ Color (ASTM)L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250or higher 250 or higher 250 or higher 250 or higher Pour point, ° C.−47.5 −42.5 −42.5 −35 −40 Kinematic viscosity, 40° C. 67.1 69.0 61.870.0 67.8 mm²/s Kinematic viscosity, 100° C. 9.88 9.26 8.71 6.99 8.34mm²/s Viscosity index 130 111 115 61 90 Moisture content, ppm 25 25 2525 25 Total acid number, 0.01 0.01 0.01 0.01 0.01 mg-KOH/g

TABLE 64 (as refrigeration oil having kinematic viscosity at 40° C. of100-320 mm²/s) Example/Comparative Example No. Example Example ExampleExample Comparative 161B 162B 163B 164B Example 34B Oil No. syntheticsynthetic synthetic synthetic comparative oil 16B oil 17B oil 24B oil25B oil 16B Density, 15° C. 1.01 1.02 1.00 0.99 1.02 g/cm³ Color (ASTM)L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250or higher 250 or higher 250 or higher 224 Pour point, ° C. −35 −37.5 −35−35 −32.5 Kinematic viscosity, 40° C. 140 139 225 276 226 mm²/sKinematic viscosity, 100° C. 13.8 13.6 18.3 20.9 21.8 mm²/s Viscosityindex 94 93 89 89 116 Moisture content, ppm 25 25 25 25 25 Total acidnumber, 0.01 0.01 0.01 0.01 0.01 mg-KOH/g

TABLE 65 (as refrigeration oil having kinematic viscosity at 40° C. of15-50 mm²/s) Example/Comparative Example No. Example Example ExampleExample Comparative 165B 166B 167B 168B Example 35B Oil No. syntheticsynthetic synthetic synthetic comparative oil 30B oil 31B oil 32B oil35B oil 17B Density, 15° C. 1.00 0.99 1.02 0.99 0.99 g/cm³ Color (ASTM)L 0.5 L 0.5 L 0.5 L 0.5 L 0.5 Flash point, COC, ° C. 250 or higher 250or higher 250 or higher 250 or higher 250 or higher Pour point, ° C.−42.5 −40 −42.5 −45 −50 Kinematic viscosity, 40° C. 29.4 36.8 47.3 26.030.3 mm²/s Kinematic viscosity, 100° C. 4.83 5.47 6.48 4.67 5.73 mm²/sViscosity index 76 76 82 93 133 Moisture content, ppm 25 25 25 25 50Total acid number, 0.01 0.01 0.01 0.01 0.02 mg-KOH/g(List of Polyol Ester Oils for Each Raw Material Combination)

The Examples and the Comparative Examples are arranged with respect toeach of raw material combinations to show that various viscosities andsolubility with various refrigerants are obtained by changing the ratioof raw materials. The relationships between the raw material combinationand kinematic viscosity or refrigerated facilities/air conditioners towhich the oil is applicable are as shown in the following Table 66 toTable 75.

TABLE 66 Raw material combination (1): alcohols, PE and DiPE; acid 1,2MBu; acid 2, 2EHx Kinematic viscosity Refrigerating Oil No. PE DiPE2MBu 2EHx (40° C.) mm²/s apparatus Synthetic 0.60 0.40 0.4 0.6 69.7 airconditioner oil 1B Synthetic 0.55 0.45 0.5 0.5 66.9 air conditioner oil2B Synthetic 0.55 0.45 0.7 0.3 66.0 air conditioner oil 3B Synthetic0.55 0.45 0.85 0.15 64.5 air conditioner oil 4B Synthetic 0.30 0.70 0.50.5 97.8 air conditioner oil 5B Synthetic 0.55 0.45 0.45 0.55 75.1 airconditioner oil 6B Synthetic 0.0 1.0 0.5 0.5 140 large refrigeratedfacility oil 16B or air conditioner Synthetic 0.0 1.0 0.7 0.3 139 largerefrigerated facility oil 17B or air conditioner Synthetic 0.0 1.0 1.00.0 141 large refrigerated facility oil 18B or air conditioner Synthetic0.10 0.90 1.0 0.0 124 large refrigerated facility oil 19B or airconditioner Synthetic 1.0 0.0 1.0 0.0 25.7 small refrigerated facilityoil 29B Synthetic 1.0 0.0 0.75 0.25 29.4 small refrigerated facility oil30B Synthetic 1.0 0.0 0.5 0.5 36.8 small refrigerated facility oil 31BSynthetic 0.70 0.30 0.85 0.15 47.2 small refrigerated facility oil 32BComparative 0.65 0.35 0.0 1.0 70.4 — oil 6B Comparative 1.0 0.0 0.0 1.044.3 — oil 11B

TABLE 67 Raw material combination (2): alcohols, PE and DiPE; acid 1,2MBu; acid 2, TMHx Kinematic viscosity Refrigerating Oil No. PE DiPE2MBu TMHx (40° C.) mm²/s apparatus Synthetic 1.0 0.0 0.5 0.5 60.0 airconditioner oil 7B Synthetic 0.50 0.50 1.0 0.0 66.1 air conditioner oil8B Synthetic 1.0 0.0 0.4 0.6 64.4 air conditioner oil 9B Synthetic 0.850.15 0.6 0.4 62.5 air conditioner oil 10B Synthetic 0.0 1.0 1.0 0.0 141large refrigerated facility oil 18B or air conditioner Synthetic 0.100.90 1.0 0.0 124 large refrigerated facility oil 19B or air conditionerSynthetic 0.70 0.30 0.5 0.5 108 large refrigerated facility oil 20B orair conditioner Synthetic 0.50 0.50 0.5 0.5 149 large refrigeratedfacility oil 21B or air conditioner Synthetic 0.30 0.70 0.5 0.5 196large refrigerated facility oil 22B or air conditioner Synthetic 0.0 1.00.9 0.1 164 large refrigerated facility oil 23B or air conditionerSynthetic 0.0 1.0 0.7 0.3 225 large refrigerated facility oil 24B or airconditioner Synthetic 0.0 1.0 0.5 0.5 276 large refrigerated facilityoil 25B or air conditioner Synthetic 1.0 0.0 1.0 0.0 25.7 smallrefrigerated facility oil 29B Synthetic 1.0 0.0 0.75 0.25 37.3 smallrefrigerated facility oil 33B Comparative 1.0 0.0 0.0 1.0 114 — oil 8Bsolidified at room temperature

TABLE 68 Raw material combination (3): alcohols, PE and DiPE; acid 1,LPt; acid 2, 2EHx Kinematic viscosity Refrigerating Oil No. PE DiPE LPt2EHx (40° C.) mm²/s apparatus Synthetic 1.0 0.0 0.5 0.5 27.8 small oil26B refrigerated facility Comparative 0.65 0.35 0.0 1.0 70.4 — oil 6BComparative 1.0 0.0 0.0 1.0 44.3 — oil 11B Comparative 1.0 0.0 0.25 0.7534.1 — oil 12B

TABLE 69 Raw material combination (4): alcohols, PE and DiPE; acid 1,LPt; acid 2, TMHx Kinematic viscosity Refrigerating Oil No. PE DiPE LPtTMHx (40° C.) mm²/s apparatus Synthetic oil 0.0 1.0 0.8 0.2 67.1 air 11Bconditioner Synthetic 1.0 0.0 0.75 0.25 24.8 small oil 27B refrigeratedfacility Synthetic 1.0 0.0 0.5 0.5 42.7 small oil 28B refrigeratedfacility Comparative 1.0 0.0 0.0 1.0 114 — oil 8B solidified at roomtemperature

TABLE 70 Raw material combination (5): alcohols, PE and DiPE; acid 1,2MPt; acid 2, 2EHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE 2MPt 2EHx mm²/s apparatus Synthetic 0.25 0.75 0.8 0.2 69.0 airconditioner oil 12B Synthetic 0.25 0.75 1.0 0.0 61.8 air conditioner oil13B Synthetic 1.0 0.0 1.0 0.0 22.4 small refrigerated oil 34B facilitySynthetic 1.0 0.0 0.75 0.25 26.0 small refrigerated oil 35B facilityComparative 0.65 0.35 0.0 1.0 70.4 — oil 6B Comparative 0.0 1.0 0.3 0.7116 — oil 10B Comparative 1.0 0.0 0.0 1.0 44.3 — oil 11B Comparative 1.00.0 0.25 0.75 36.4 — oil 14B

TABLE 71 Raw material combination (6): alcohols, PE and DiPE; acid 1,2MPt; acid 2, TMHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE 2MPt TMHx mm²/s apparatus Synthetic 0.25 0.75 1.0 0.0 61.8 air oil13B conditioner Synthetic 1.0 0.0 0.5 0.5 53.9 air oil 14B conditionerSynthetic 1.0 0.0 1.0 0.0 22.4 small oil 34B refrigerated facilityComparative 1.0 0.0 0.0 1.0 114 — oil 8B solidified at room temperature

TABLE 72 Raw material combination (7): alcohols, PE and DiPE; acid 1,2EBu; acid 2, TMHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE 2EBu TMHx mm²/s apparatus Synthetic 1.0 0.0 0.75 0.25 70.0 airconditioner oil 15B Comparative 1.0 0.0 0.0 1.0 114 — oil 8B solidifiedat room temperature

TABLE 73 Raw material combination (8): alcohols, PE and DiPE; acid 1,LHx; acid 2, TMHx Kinematic viscosity Refrigerating Oil No. PE DiPE LHxTMHx (40° C.) mm²/s apparatus Comparative 1.0 0.0 0.25 0.75 64.6 — oil2B Comparative 0.0 1.0 0.67 0.33 88.0 — oil 3B Comparative 0.0 1.0 1.00.0 53.0 — oil 4B solidified at room temperature Comparative 0.0 1.0 0.30.7 181 — oil 7B Comparative 1.0 0.0 0.0 1.0 114 — oil 8B solidified atroom temperature Comparative 1.0 0.0 0.5 0.5 40.5 — oil 13B

TABLE 74 Raw material combination (9): alcohols, PE and DiPE; acid 1,2EHx; acid 2, TMHx Kinematic viscosity (40° C.) Refrigerating Oil No. PEDiPE 2EHx TMHx mm²/s apparatus Comparative 1.0 0.0 0.5 0.5 67.8 air oil1B conditioner Comparative 0.65 0.35 1.0 0.0 70.4 — oil 6B Comparative1.0 0.0 0.0 1.0 114 — oil 8B solidified at room temperature Comparative0.0 1.0 0.5 0.5 228 — oil 9B Comparative 1.0 0.0 1.0 0.0 44.3 — oil 11B

TABLE 75 Other combinations Kinematic viscosity (40° C.) RefrigeratingOil No. PE DiPE Acids mm²/s apparatus Comparative 0.8 0.2 LPt: 0.4 30.3small oil 17B n-heptanoic refrigerated acid: 0.4 facility MHx: 0.2Comparative refrigerant R-290/mineral oil 95.9 air oil 15B for airconditioner conditioner Comparative complex ester obtained 226 large oil16B from PE, 2EHx, adipic refrigerated acid, etc. facility or airconditioner Refrigerating Alcohol: neopentyl glycol 7.56 domesticmachine Fatty acid: 2EHx refrigerator oil B

The relationship between each raw material combination and thesolubility with each refrigerant (low-temperature-side two-layerseparation temperature) is as shown in the following Table 76 to Table85.

TABLE 76 Alcohols, PE and DiPE; acid 1, 2MBu; acid 2, 2EHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2MBu 2EHx R-290 R-600a R-1270 Synthetic 0.600.40 0.4 0.6 −50 or lower −50 or lower −50 or lower oil 1B Synthetic0.55 0.45 0.5 0.5 −50 or lower −50 or lower −50 or lower oil 2BSynthetic 0.55 0.45 0.7 0.3 −50 or lower −50 or lower −50 or lower oil3B Synthetic 0.55 0.45 0.85 0.15 −50 or lower −50 or lower −50 or loweroil 4B Synthetic 0.30 0.70 0.5 0.5 −50 or lower −50 or lower −50 orlower oil 5B Synthetic 0.55 0.45 0.45 0.55 −50 or lower −50 or lower −50or lower oil 6B Synthetic 0.0 1.0 0.5 0.5 −50 or lower −50 or lower −50or lower oil 16B Synthetic 0.0 1.0 0.7 0.3 −50 or lower −50 or lower −50or lower oil 17B Synthetic 0.0 1.0 1.0 0.0 −50 or lower −50 or lower −50or lower oil 18B Synthetic 0.10 0.90 1.0 0.0 −50 or lower −50 or lower−50 or lower oil 19B Synthetic 1.0 0.0 1.0 0.0 −50 or lower −50 or lower−50 or lower oil 29B Synthetic 1.0 0.0 0.75 0.25 −50 or lower −50 orlower −50 or lower oil 30B Synthetic 1.0 0.0 0.5 0.5 −50 or lower −50 orlower −50 or lower oil 31B Synthetic 0.70 0.30 0.85 0.15 −50 or lower−50 or lower −50 or lower oil 32B Comparative 0.65 0.35 0.0 1.0 −50 orlower −50 or lower −50 or lower oil 6B Comparative 1.0 0.0 0.0 1.0 −50or lower −50 or lower −50 or lower oil 11B

TABLE 77 Alcohols, PE and DiPE; acid 1, 2MBu; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2MBu TMHx R-290 R-600a R-1270 Synthetic 1.00.0 0.5 0.5 −50 or lower −50 or lower −50 or lower oil 7B Synthetic 0.500.50 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 8B Synthetic 1.00.0 0.4 0.6 −50 or lower −50 or lower −50 or lower oil 9B Synthetic 0.850.15 0.6 0.4 −50 or lower −50 or lower −50 or lower oil 10B Synthetic0.0 1.0 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 18B Synthetic0.10 0.90 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 19BSynthetic 0.70 0.30 0.5 0.5 −50 or lower −50 or lower −50 or lower oil20B Synthetic 0.50 0.50 0.5 0.5 −50 or lower −50 or lower −50 or loweroil 21B Synthetic 0.30 0.70 0.5 0.5 −50 or lower −50 or lower −50 orlower oil 22B Synthetic 0.0 1.0 0.9 0.1 −50 or lower −50 or lower −50 orlower oil 23B Synthetic 0.0 1.0 0.7 0.3 −50 or lower −50 or lower −50 orlower oil 24B Synthetic 0.0 1.0 0.5 0.5 −50 or lower −50 or lower −50 orlower oil 25B Synthetic 1.0 0.0 1.0 0.0 −50 or lower −50 or lower −50 orlower oil 29B Synthetic 1.0 0.0 0.75 0.25 −50 or lower −50 or lower −50or lower oil 33B Comparative 1.0 0.0 0.0 1.0 −50 or lower −50 or lower−50 or lower oil 8B

TABLE 78 Alcohols, PE and DiPE; acid 1, LPt; acid 2, 2EHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE LPt 2EHx R-290 R-600a R-1270 Synthetic 1.00.0 0.5 0.5 −50 or lower −50 or lower −50 or lower oil 26B Comparative0.65 0.35 0.0 1.0 −50 or lower −50 or lower −50 or lower oil 6BComparative 1.0 0.0 0.0 1.0 −50 or lower −50 or lower −50 or lower oil11B Comparative 1.0 0.0 0.25 0.75 −50 or lower −50 or lower −50 or loweroil 12B

TABLE 79 Alcohols, PE and DiPE; acid 1, LPt; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE LPt TMHx R-290 R-600a R-1270 Synthetic 0.01.0 0.8 0.2 −50 or lower −50 or lower −50 or lower oil 11B Synthetic 1.00.0 0.75 0.25 −50 or lower −50 or lower −50 or lower oil 27B Synthetic1.0 0.0 0.5 0.5 −50 or lower −50 or lower −50 or lower oil 28BComparative 1.0 0.0 0.0 1.0 −50 or lower −50 or lower −50 or lower oil8B

TABLE 80 Alcohols, PE and DiPE; acid 1, 2MPt; acid 2, 2EHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2MPt 2EHx R-290 R-600a R-1270 Synthetic 0.250.75 0.8 0.2 −50 or lower −50 or lower −50 or lower oil 12B Synthetic0.25 0.75 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 13BSynthetic 1.0 0.0 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 34BSynthetic 1.0 0.0 0.75 0.25 −50 or lower −50 or lower −50 or lower oil35B Comparative 0.65 0.35 0.0 1.0 −50 or lower −50 or lower −50 or loweroil 6B Comparative 0.0 1.0 0.3 0.7 −50 or lower −50 or lower −50 orlower oil 10B Comparative 1.0 0.0 0.0 1.0 −50 or lower −50 or lower −50or lower oil 11B Comparative 1.0 0.0 0.25 0.75 +32 −19 −50 or lower oil14B

TABLE 81 Alcohols, PE and DiPE; acid 1, 2MPt; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2MPt 2EHx R-290 R-600a R-1270 Synthetic 0.250.75 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 13B Synthetic1.0 0.0 0.5 0.5 −50 or lower −50 or lower −50 or lower oil 14B Synthetic1.0 0.0 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 34BComparative 1.0 0.0 0.0 1.0 −50 or lower −50 or lower −50 or lower oil8B

TABLE 82 Alcohols, PE and DiPE; acid 1, 2EBu; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2EBu TMHx R-290 R-600a R-1270 Synthetic 1.00.0 0.75 0.25 −50 or lower −50 or lower −50 or lower oil 15B Comparative1.0 0.0 0.0 1.0 −50 or lower −50 or lower −50 or lower oil 8B

TABLE 83 Alcohols, PE and DiPE; acid 1, LHx; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE LHx TMHx R-290 R-600a R-1270 Comparative 1.00.0 0.25 0.75 −50 or lower −50 or lower −50 or lower oil 2B Comparative0.0 1.0 0.67 0.33 −50 or lower −50 or lower −50 or lower oil 3BComparative 0.0 1.0 0.3 0.7 −50 or lower −50 or lower −50 or lower oil7B Comparative 1.0 0.0 0.0 1.0 −50 or lower −50 or lower −50 or loweroil 8A Comparative 1.0 0.0 0.5 0.5 −50 or lower −50 or lower −50 orlower oil 13B

TABLE 84 Alcohols, PE and DiPE; acid 1, 2EHx; acid 2, TMHxLow-temperature-side two-layer separation temperature (oil content,20%), ° C. Oil No. PE DiPE 2EHx TMHx R-290 R-600a R-1270 Comparative 1.00.0 0.5 0.5 −50 or lower −50 or lower −50 or lower oil 1B Comparative0.65 0.35 1.0 0.0 −50 or lower −50 or lower −50 or lower oil 6BComparative 1.0 0.0 0.0 1.0 −50 or lower −50 or lower −50 or lower oil8B Comparative 0.0 1.0 0.5 0.5 −50 or lower −50 or lower −50 or loweroil 9B Comparative 1.0 0.0 1.0 0.0 −50 or lower −50 or lower −50 or lessoil 11B

TABLE 85 Other combinations Low-temperature-side two-layer separationtemperature (oil content, 20%), ° C. Oil No. PE DiPE Acids R-290 R-600aR-1270 Comparative 0.8 0.2 LPt: 0.4 −50 or lower −50 or lower −50 orlower oil 17B n-heptanoic acid: 0.4 TMHx: 0.2 Comparative refrigerantR-290/mineral oil −50 or lower −50 or lower −50 or lower oil 15B for airconditioner Comparative complex ester obtained from −50 or lower −50 orlower −50 or lower oil 16B PE, 2EHx, adipic acid, etc. RefrigeratingAlcohol: neopentyl glycol −50 or lower −50 or lower −50 or lower machineFatty acid: 2EHx oil B

As shown in Table 66 to Table 75, the polyol ester oils each produced byesterifying an alcohol ingredient obtained by mixing pentaerythritolwith dipentaerythritol and a fatty acid ingredient composed of at leastone of pentanoic acid and hexanoic acid and at least one of octanoicacid and nonanoic acid are made to have various values of viscosity bychanging the proportions of the raw materials with respect to each ofspecific raw material combinations.

Furthermore, as shown in Table 49 to Table 56, refrigeration oilcompositions which are excellent in terms of solubility and lubricitycan be produced even with hydrocarbon refrigerants having an exceedinglylow global warming potential, by using polyol ester oils each producedby esterifying an alcohol ingredient obtained by mixing pentaerythritolwith dipentaerythritol and a fatty acid ingredient composed of at leastone of pentanoic acid and hexanoic acid and at least one of octanoicacid and nonanoic acid.

Moreover, as shown in Table 61 to Table 65, the polyol ester oils eachproduced by esterifying an alcohol ingredient obtained by mixingpentaerythritol with dipentaerythritol and a fatty acid ingredientcomposed of at least one of pentanoic acid and hexanoic acid and atleast one of octanoic acid and nonanoic acid have the properties andperformances which are required of refrigeration oils, as compared withthe mineral oil (comparative oil 15B) for refrigerant R290 and withComparative Example 1B, etc.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

This application is based on a Japanese patent application filed on Dec.27, 2011 (Application No. 2011-286045) and a Japanese patent applicationfiled on Dec. 12, 2012 (Application No. 2012-270435), the contentsthereof being incorporated herein by reference.

INDUSTRIAL APPLICABILITY

The present invention is useful as refrigeration oil compositions forhydrofluorocarbon-based refrigerants or hydrocarbon-based refrigerants.

The invention claimed is:
 1. A working fluid, comprising: a hydrofluorocarbon-based refrigerant; and a refrigeration oil composition containing a polyol ester oil which is soluble with the hydrofluorocarbon-based refrigerant, wherein the refrigerant consists essentially of R-32, the polyol ester oil is a product of esterification of an alcohol ingredient containing pentaerythritol and dipentaerythritol and a fatty acid ingredient consisting of 2 methylbutanoic acid and at least one of 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid, and the 2-methylbutanoic acid accounts for 20 to 90 mole % of the total amount of the fatty acid ingredient.
 2. The working fluid according to claim 1, wherein the hydrofluorocarbon-based refrigerant is soluble with the refrigeration oil composition in a range of +35° C. to +25° C.
 3. The working fluid according to claim 1, further comprising at least one of an antioxidant, an epoxy-compound acid scavenger, and an extreme-pressure agent.
 4. The working fluid according to claim 1, wherein the hydrofluorocarbon-based refrigerant composition contains at least one selected from the group consisting of R-32, R410A, and HFO-1234ze(E).
 5. The working fluid according to claim 1, wherein the hydrofluorocarbon-based refrigerant composition consists of R-32 as the refrigerant. 